diff --git a/README.md b/README.md
index 0146874..d5cdcac 100755
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@
 
 ### Function Overview
 
-The solution backs up all volumes attached to VMs which have a pre-defined metadata set, for
+The solution backs up all volumes attached to VMs which have a predefined metadata set, for
 example, `backup=yes`.
 First, it gets the list of VMs which have backup metadata and the list of volumes attached to the
 VMs in the given project by consuming the Openstack API (nova-api and cinder-api). Once the
diff --git a/doc/source/conf.py b/doc/source/conf.py
index e41b2c9..3588b3d 100755
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -15,14 +15,14 @@
 import os
 import sys
 
-sys.path.insert(0, os.path.abspath('../..'))
+sys.path.insert(0, os.path.abspath("../.."))
 # -- General configuration ----------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
-    'sphinx.ext.autodoc',
-    'openstackdocstheme',
+    "sphinx.ext.autodoc",
+    "openstackdocstheme",
     #'sphinx.ext.intersphinx',
 ]
 
@@ -31,19 +31,21 @@
 # execute "export SPHINX_DEBUG=1" in your terminal to disable
 
 # The suffix of source filenames.
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = u'staffeln'
-copyright = u'2017, OpenStack Developers'
+project = "staffeln"
+copyright = "2017, OpenStack Developers"
 
 # openstackdocstheme options
-openstackdocs_repo_name = 'openstack/staffeln'
-openstackdocs_bug_project = 'replace with the name of the project on Launchpad or the ID from Storyboard'
-openstackdocs_bug_tag = ''
+openstackdocs_repo_name = "openstack/staffeln"
+openstackdocs_bug_project = (
+    "replace with the name of the project on Launchpad or the ID from Storyboard"
+)
+openstackdocs_bug_tag = ""
 
 # If true, '()' will be appended to :func: etc. cross-reference text.
 add_function_parentheses = True
@@ -53,7 +55,7 @@
 add_module_names = True
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'native'
+pygments_style = "native"
 
 # -- Options for HTML output --------------------------------------------------
 
@@ -62,20 +64,23 @@
 # html_theme_path = ["."]
 # html_theme = '_theme'
 # html_static_path = ['static']
-html_theme = 'openstackdocs'
+html_theme = "openstackdocs"
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = '%sdoc' % project
+htmlhelp_basename = "%sdoc" % project
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass
 # [howto/manual]).
 latex_documents = [
-    ('index',
-     '%s.tex' % project,
-     u'%s Documentation' % project,
-     u'OpenStack Developers', 'manual'),
+    (
+        "index",
+        "%s.tex" % project,
+        "%s Documentation" % project,
+        "OpenStack Developers",
+        "manual",
+    ),
 ]
 
 # Example configuration for intersphinx: refer to the Python standard library.
-#intersphinx_mapping = {'http://docs.python.org/': None}
+# intersphinx_mapping = {'http://docs.python.org/': None}
diff --git a/releasenotes/source/conf.py b/releasenotes/source/conf.py
index b3a878b..65d2460 100755
--- a/releasenotes/source/conf.py
+++ b/releasenotes/source/conf.py
@@ -35,32 +35,32 @@
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
-    'openstackdocstheme',
-    'reno.sphinxext',
+    "openstackdocstheme",
+    "reno.sphinxext",
 ]
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix of source filenames.
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The encoding of source files.
 # source_encoding = 'utf-8-sig'
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = u'staffeln Release Notes'
-copyright = u'2017, OpenStack Developers'
+project = "staffeln Release Notes"
+copyright = "2017, OpenStack Developers"
 
 # openstackdocstheme options
-openstackdocs_repo_name = 'openstack/staffeln'
+openstackdocs_repo_name = "openstack/staffeln"
 openstackdocs_bug_project = """replace with the name of the
 project on Launchpad or the ID from Storyboard"""
-openstackdocs_bug_tag = ''
-openstackdocs_auto_name = 'False'
+openstackdocs_bug_tag = ""
+openstackdocs_auto_name = "False"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -68,9 +68,9 @@
 #
 # The short X.Y version.
 # The full version, including alpha/beta/rc tags.
-release = ''
+release = ""
 # The short X.Y version.
-version = ''
+version = ""
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -102,7 +102,7 @@
 # show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'native'
+pygments_style = "native"
 
 # A list of ignored prefixes for module index sorting.
 # modindex_common_prefix = []
@@ -115,7 +115,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'openstackdocs'
+html_theme = "openstackdocs"
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
@@ -144,7 +144,7 @@
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+html_static_path = ["_static"]
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied
@@ -189,7 +189,7 @@
 # html_file_suffix = None
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'staffelnReleaseNotesdoc'
+htmlhelp_basename = "staffelnReleaseNotesdoc"
 
 
 # -- Options for LaTeX output ---------------------------------------------
@@ -197,10 +197,8 @@
 latex_elements = {
     # The paper size ('letterpaper' or 'a4paper').
     # 'papersize': 'letterpaper',
-
     # The font size ('10pt', '11pt' or '12pt').
     # 'pointsize': '10pt',
-
     # Additional stuff for the LaTeX preamble.
     # 'preamble': '',
 }
@@ -209,9 +207,13 @@
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
-    ('index', 'staffelnReleaseNotes.tex',
-     u'staffeln  Release Notes Documentation',
-     u'OpenStack Foundation', 'manual'),
+    (
+        "index",
+        "staffelnReleaseNotes.tex",
+        "staffeln  Release Notes Documentation",
+        "OpenStack Foundation",
+        "manual",
+    ),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
@@ -240,9 +242,13 @@
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
 man_pages = [
-    ('index', 'staffelnrereleasenotes',
-     u'staffeln  Release Notes Documentation',
-     [u'OpenStack Foundation'], 1)
+    (
+        "index",
+        "staffelnrereleasenotes",
+        "staffeln  Release Notes Documentation",
+        ["OpenStack Foundation"],
+        1,
+    )
 ]
 
 # If true, show URL addresses after external links.
@@ -255,11 +261,15 @@
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-    ('index', 'staffeln ReleaseNotes',
-     u'staffeln Release Notes Documentation',
-     u'OpenStack Foundation', 'staffelnReleaseNotes',
-     'One line description of project.',
-     'Miscellaneous'),
+    (
+        "index",
+        "staffeln ReleaseNotes",
+        "staffeln Release Notes Documentation",
+        "OpenStack Foundation",
+        "staffelnReleaseNotes",
+        "One line description of project.",
+        "Miscellaneous",
+    ),
 ]
 
 # Documents to append as an appendix to all manuals.
@@ -275,4 +285,4 @@
 # texinfo_no_detailmenu = False
 
 # -- Options for Internationalization output ------------------------------
-locale_dirs = ['locale/']
+locale_dirs = ["locale/"]
diff --git a/setup.py b/setup.py
index 1f988cd..0346ed3 100755
--- a/setup.py
+++ b/setup.py
@@ -16,6 +16,4 @@
 # THIS FILE IS MANAGED BY THE GLOBAL REQUIREMENTS REPO - DO NOT EDIT
 import setuptools
 
-setuptools.setup(
-    setup_requires=['pbr'],
-    pbr=True)
+setuptools.setup(setup_requires=["pbr"], pbr=True)
diff --git a/staffeln/__init__.py b/staffeln/__init__.py
index 686f74c..553afa9 100755
--- a/staffeln/__init__.py
+++ b/staffeln/__init__.py
@@ -15,5 +15,4 @@
 import pbr.version
 
 
-__version__ = pbr.version.VersionInfo(
-    'staffeln').version_string()
+__version__ = pbr.version.VersionInfo("staffeln").version_string()
diff --git a/staffeln/api/app.py b/staffeln/api/app.py
index 9552746..e506dd6 100755
--- a/staffeln/api/app.py
+++ b/staffeln/api/app.py
@@ -14,7 +14,7 @@
 
 @app.route("/v1/backup", methods=["POST"])
 def backup_id():
-    
+
     if "backup_id" not in request.args:
         # Return error if the backup_id argument is not provided.
         return Response(
diff --git a/staffeln/api/middleware/parsable_error.py b/staffeln/api/middleware/parsable_error.py
index d7ce289..05297b2 100755
--- a/staffeln/api/middleware/parsable_error.py
+++ b/staffeln/api/middleware/parsable_error.py
@@ -25,6 +25,7 @@
 
 class ParsableErrorMiddleware(object):
     """Replace error body with something the client can parse."""
+
     def __init__(self, app):
         self.app = app
 
@@ -33,33 +34,36 @@
         for err_str in app_iter:
             err = {}
             try:
-                err = jsonutils.loads(err_str.decode('utf-8'))
+                err = jsonutils.loads(err_str.decode("utf-8"))
             except ValueError:
                 pass
 
-            if 'title' in err and 'description' in err:
-                title = err['title']
-                desc = err['description']
-            elif 'faultstring' in err:
-                title = err['faultstring'].split('.', 1)[0]
-                desc = err['faultstring']
+            if "title" in err and "description" in err:
+                title = err["title"]
+                desc = err["description"]
+            elif "faultstring" in err:
+                title = err["faultstring"].split(".", 1)[0]
+                desc = err["faultstring"]
             else:
-                title = ''
-                desc = ''
+                title = ""
+                desc = ""
 
-            code = err['faultcode'].lower() if 'faultcode' in err else ''
+            code = err["faultcode"].lower() if "faultcode" in err else ""
 
             # if already formatted by custom exception, don't update
-            if 'min_version' in err:
+            if "min_version" in err:
                 errs.append(err)
             else:
-                errs.append({
-                    'request_id': '',
-                    'code': code,
-                    'status': status_code,
-                    'title': title,
-                    'detail': desc,
-                    'links': []})
+                errs.append(
+                    {
+                        "request_id": "",
+                        "code": code,
+                        "status": status_code,
+                        "title": title,
+                        "detail": desc,
+                        "links": [],
+                    }
+                )
 
         return errs
 
@@ -71,33 +75,35 @@
         def replacement_start_response(status, headers, exc_info=None):
             """Overrides the default response to make errors parsable."""
             try:
-                status_code = int(status.split(' ')[0])
-                state['status_code'] = status_code
+                status_code = int(status.split(" ")[0])
+                state["status_code"] = status_code
             except (ValueError, TypeError):  # pragma: nocover
-                raise Exception(_(
-                    'ErrorDocumentMiddleware received an invalid '
-                    'status %s') % status)
+                raise Exception(
+                    _("ErrorDocumentMiddleware received an invalid " "status %s")
+                    % status
+                )
             else:
-                if (state['status_code'] // 100) not in (2, 3):
+                if (state["status_code"] // 100) not in (2, 3):
                     # Remove some headers so we can replace them later
                     # when we have the full error message and can
                     # compute the length.
-                    headers = [(h, v)
-                               for (h, v) in headers
-                               if h not in ('Content-Length', 'Content-Type')
-                               ]
+                    headers = [
+                        (h, v)
+                        for (h, v) in headers
+                        if h not in ("Content-Length", "Content-Type")
+                    ]
                 # Save the headers in case we need to modify them.
-                state['headers'] = headers
+                state["headers"] = headers
 
                 return start_response(status, headers, exc_info)
 
         app_iter = self.app(environ, replacement_start_response)
 
-        if (state['status_code'] // 100) not in (2, 3):
-            errs = self._update_errors(app_iter, state['status_code'])
-            body = [jsonutils.dump_as_bytes({'errors': errs})]
-            state['headers'].append(('Content-Type', 'application/json'))
-            state['headers'].append(('Content-Length', str(len(body[0]))))
+        if (state["status_code"] // 100) not in (2, 3):
+            errs = self._update_errors(app_iter, state["status_code"])
+            body = [jsonutils.dump_as_bytes({"errors": errs})]
+            state["headers"].append(("Content-Type", "application/json"))
+            state["headers"].append(("Content-Length", str(len(body[0]))))
 
         else:
             body = app_iter
diff --git a/staffeln/cmd/api.py b/staffeln/cmd/api.py
index f554354..0280a66 100755
--- a/staffeln/cmd/api.py
+++ b/staffeln/cmd/api.py
@@ -21,12 +21,10 @@
         key_file = CONF.api.ssl_key_file
 
         if cert_file and not os.path.exists(cert_file):
-            raise RuntimeError(
-                _("Unable to find cert_file : %s") % cert_file)
+            raise RuntimeError(_("Unable to find cert_file : %s") % cert_file)
 
         if key_file and not os.path.exists(key_file):
-            raise RuntimeError(
-                _("Unable to find key_file : %s") % key_file)
+            raise RuntimeError(_("Unable to find key_file : %s") % key_file)
 
         return cert_file, key_file
     else:
@@ -42,11 +40,13 @@
     # Create the WSGI server and start it
     host, port = CONF.api.host, CONF.api.port
 
-    LOG.info('Starting server in PID %s', os.getpid())
+    LOG.info("Starting server in PID %s", os.getpid())
     LOG.debug("Configuration:")
     CONF.log_opt_values(LOG, logging.DEBUG)
 
-    LOG.info('Serving on %(proto)s://%(host)s:%(port)s',
-             dict(proto="https" if use_ssl else "http", host=host, port=port))
+    LOG.info(
+        "Serving on %(proto)s://%(host)s:%(port)s",
+        dict(proto="https" if use_ssl else "http", host=host, port=port),
+    )
 
     api_app.run(host=host, port=port, ssl_context=_get_ssl_configs(use_ssl))
diff --git a/staffeln/cmd/conductor.py b/staffeln/cmd/conductor.py
index 2550d88..24ba590 100755
--- a/staffeln/cmd/conductor.py
+++ b/staffeln/cmd/conductor.py
@@ -14,9 +14,9 @@
     service.prepare_service()
 
     sm = cotyledon.ServiceManager()
-    sm.add(manager.BackupManager,
-           workers=CONF.conductor.backup_workers, args=(CONF,))
-    sm.add(manager.RotationManager,
-           workers=CONF.conductor.rotation_workers, args=(CONF,))
+    sm.add(manager.BackupManager, workers=CONF.conductor.backup_workers, args=(CONF,))
+    sm.add(
+        manager.RotationManager, workers=CONF.conductor.rotation_workers, args=(CONF,)
+    )
     oslo_config_glue.setup(sm, CONF)
     sm.run()
diff --git a/staffeln/cmd/dbmanage.py b/staffeln/cmd/dbmanage.py
index 89b69ba..467b52a 100644
--- a/staffeln/cmd/dbmanage.py
+++ b/staffeln/cmd/dbmanage.py
@@ -15,7 +15,6 @@
 
 
 class DBCommand(object):
-
     @staticmethod
     def create_schema():
         migration.create_schema()
@@ -23,16 +22,13 @@
 
 def add_command_parsers(subparsers):
 
-    parser = subparsers.add_parser(
-        'create_schema',
-        help="Create the database schema.")
+    parser = subparsers.add_parser("create_schema", help="Create the database schema.")
     parser.set_defaults(func=DBCommand.create_schema)
 
 
-command_opt = cfg.SubCommandOpt('command',
-                                title='Command',
-                                help='Available commands',
-                                handler=add_command_parsers)
+command_opt = cfg.SubCommandOpt(
+    "command", title="Command", help="Available commands", handler=add_command_parsers
+)
 
 
 def register_sub_command_opts():
@@ -42,11 +38,13 @@
 def main():
     register_sub_command_opts()
 
-    valid_commands = set([
-        'create_schema',
-    ])
+    valid_commands = set(
+        [
+            "create_schema",
+        ]
+    )
     if not set(sys.argv).intersection(valid_commands):
-        sys.argv.append('create_schema')
+        sys.argv.append("create_schema")
 
     service.prepare_service(sys.argv)
     CONF.command.func()
diff --git a/staffeln/common/config.py b/staffeln/common/config.py
index dd28201..f71a378 100755
--- a/staffeln/common/config.py
+++ b/staffeln/common/config.py
@@ -7,10 +7,12 @@
 
 def parse_args(argv, default_config_files=None):
     # rpc.set_defaults(control_exchange='staffeln')
-    CONF(argv[1:],
-         project='staffeln',
-         version=version.version_info.release_string(),
-         default_config_files=default_config_files)
+    CONF(
+        argv[1:],
+        project="staffeln",
+        version=version.version_info.release_string(),
+        default_config_files=default_config_files,
+    )
     # rpc.init(CONF)
 
 
diff --git a/staffeln/common/constants.py b/staffeln/common/constants.py
index 91b2a95..6b60ef5 100644
--- a/staffeln/common/constants.py
+++ b/staffeln/common/constants.py
@@ -1,9 +1,9 @@
-BACKUP_COMPLETED=2
-BACKUP_WIP=1
-BACKUP_PLANNED=0
+BACKUP_COMPLETED = 2
+BACKUP_WIP = 1
+BACKUP_PLANNED = 0
 
-BACKUP_ENABLED_KEY = 'true'
-BACKUP_RESULT_CHECK_INTERVAL = 60 # second
+BACKUP_ENABLED_KEY = "true"
+BACKUP_RESULT_CHECK_INTERVAL = 60  # second
 
 # default config values
-DEFAULT_BACKUP_CYCLE_TIMEOUT="5min"
\ No newline at end of file
+DEFAULT_BACKUP_CYCLE_TIMEOUT = "5min"
diff --git a/staffeln/common/email.py b/staffeln/common/email.py
index d88a96d..c5c4b70 100644
--- a/staffeln/common/email.py
+++ b/staffeln/common/email.py
@@ -8,13 +8,13 @@
 
 
 def send(
-        src_email,
-        src_pwd,
-        dest_email,
-        subject,
-        content,
-        smtp_server_domain,
-        smtp_server_port,
+    src_email,
+    src_pwd,
+    dest_email,
+    subject,
+    content,
+    smtp_server_domain,
+    smtp_server_port,
 ):
     message = MIMEMultipart("alternative")
     message["Subject"] = subject
diff --git a/staffeln/common/openstack.py b/staffeln/common/openstack.py
index 7aaf1a0..c6d2769 100644
--- a/staffeln/common/openstack.py
+++ b/staffeln/common/openstack.py
@@ -7,25 +7,22 @@
 LOG = log.getLogger(__name__)
 
 
-class OpenstackSDK():
-
+class OpenstackSDK:
     def __init__(self):
         self.conn_list = {}
         self.conn = auth.create_connection()
 
-
     def set_project(self, project):
-        LOG.debug(_("Connect as project %s" % project.get('name')))
-        project_id = project.get('id')
+        LOG.debug(_("Connect as project %s" % project.get("name")))
+        project_id = project.get("id")
 
         if project_id not in self.conn_list:
-            LOG.debug(_("Initiate connection for project %s" % project.get('name')))
+            LOG.debug(_("Initiate connection for project %s" % project.get("name")))
             conn = self.conn.connect_as_project(project)
             self.conn_list[project_id] = conn
-        LOG.debug(_("Connect as project %s" % project.get('name')))
+        LOG.debug(_("Connect as project %s" % project.get("name")))
         self.conn = self.conn_list[project_id]
 
-
     # user
     def get_user_id(self):
         user_name = self.conn.config.auth["username"]
@@ -43,19 +40,16 @@
     def get_projects(self):
         return self.conn.list_projects()
 
-
     ############## server
     def get_servers(self, project_id, all_projects=True, details=True):
         return self.conn.compute.servers(
             details=details, all_projects=all_projects, project_id=project_id
         )
 
-
     ############## volume
     def get_volume(self, uuid, project_id):
         return self.conn.get_volume_by_id(uuid)
 
-
     ############## backup
     def get_backup(self, uuid, project_id=None):
         # return conn.block_storage.get_backup(
@@ -67,16 +61,16 @@
         except exceptions.ResourceNotFound:
             return None
 
-
     def create_backup(self, volume_id, project_id, force=True, wait=False):
         # return conn.block_storage.create_backup(
         #     volume_id=queue.volume_id, force=True, project_id=queue.project_id,
         # )
         return self.conn.create_volume_backup(
-            volume_id=volume_id, force=force, wait=wait,
+            volume_id=volume_id,
+            force=force,
+            wait=wait,
         )
 
-
     def delete_backup(self, uuid, project_id=None, force=False):
         # Note(Alex): v3 is not supporting force delete?
         # conn.block_storage.delete_backup(
@@ -88,18 +82,16 @@
         except exceptions.ResourceNotFound:
             return None
 
-
     def get_backup_quota(self, project_id):
         # quota = conn.get_volume_quotas(project_id)
         quota = self._get_volume_quotas(project_id)
         return quota.backups
 
-
     # rewrite openstasdk._block_storage.get_volume_quotas
     # added usage flag
     # ref: https://docs.openstack.org/api-ref/block-storage/v3/?expanded=#show-quota-usage-for-a-project
     def _get_volume_quotas(self, project_id, usage=True):
-        """ Get volume quotas for a project
+        """Get volume quotas for a project
 
         :param name_or_id: project name or id
         :raises: OpenStackCloudException if it's not a valid project
@@ -109,12 +101,11 @@
 
         if usage:
             resp = self.conn.block_storage.get(
-                '/os-quota-sets/{project_id}?usage=True'.format(project_id=project_id))
+                "/os-quota-sets/{project_id}?usage=True".format(project_id=project_id)
+            )
         else:
             resp = self.conn.block_storage.get(
-                '/os-quota-sets/{project_id}'.format(project_id=project_id))
-        data = proxy._json_response(
-            resp,
-            error_message="cinder client call failed")
-        return self.conn._get_and_munchify('quota_set', data)
-
+                "/os-quota-sets/{project_id}".format(project_id=project_id)
+            )
+        data = proxy._json_response(resp, error_message="cinder client call failed")
+        return self.conn._get_and_munchify("quota_set", data)
diff --git a/staffeln/common/service.py b/staffeln/common/service.py
index 791955b..e35da2a 100755
--- a/staffeln/common/service.py
+++ b/staffeln/common/service.py
@@ -28,4 +28,4 @@
     config.parse_args(argv)
     config.set_config_defaults()
     objects.register_all()
-    logging.setup(CONF, 'staffeln')
+    logging.setup(CONF, "staffeln")
diff --git a/staffeln/common/short_id.py b/staffeln/common/short_id.py
index be719c9..9350258 100755
--- a/staffeln/common/short_id.py
+++ b/staffeln/common/short_id.py
@@ -17,9 +17,10 @@
     required.
     """
     shifts = six.moves.xrange(num_bits - 8, -8, -8)
-    byte_at = lambda off: ((value >> off  # noqa: E731
-                            if off >= 0 else value << -off) & 0xff)
-    return ''.join(chr(byte_at(offset)) for offset in shifts)
+    byte_at = lambda off: (
+        (value >> off if off >= 0 else value << -off) & 0xFF  # noqa: E731
+    )
+    return "".join(chr(byte_at(offset)) for offset in shifts)
 
 
 def get_id(source_uuid):
@@ -30,7 +31,7 @@
     if isinstance(source_uuid, six.string_types):
         source_uuid = uuid.UUID(source_uuid)
     if source_uuid.version != 4:
-        raise ValueError(_('Invalid UUID version (%d)') % source_uuid.version)
+        raise ValueError(_("Invalid UUID version (%d)") % source_uuid.version)
 
     # The "time" field of a v4 UUID contains 60 random bits
     # (see RFC4122, Section 4.4)
@@ -39,7 +40,7 @@
     encoded = base64.b32encode(six.b(random_bytes))[:12]
 
     if six.PY3:
-        return encoded.lower().decode('utf-8')
+        return encoded.lower().decode("utf-8")
     else:
         return encoded.lower()
 
diff --git a/staffeln/common/time.py b/staffeln/common/time.py
index 02e40e1..fd045dd 100644
--- a/staffeln/common/time.py
+++ b/staffeln/common/time.py
@@ -5,7 +5,7 @@
 DEFAULT_TIME_FORMAT = "%Y-%m-%d %H:%M:%S"
 
 regex = re.compile(
-    r'((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?'
+    r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?"
 )
 
 
@@ -26,25 +26,37 @@
                 empty_flag = False
             else:
                 time_params[key] = 0
-        if empty_flag: return None
+        if empty_flag:
+            return None
         return time_params
     except:
         return None
 
+
 def get_current_time():
     return datetime.now()
 
+
 def get_current_strtime():
     now = datetime.now()
     return now.strftime(DEFAULT_TIME_FORMAT)
 
 
-def timeago(years=0, months=0, weeks=0, days=0, hours=0, minutes=0, seconds=0, from_date=None):
+def timeago(
+    years=0, months=0, weeks=0, days=0, hours=0, minutes=0, seconds=0, from_date=None
+):
     if from_date is None:
         from_date = datetime.now()
-    return from_date - relativedelta(years=years, months=months,
-                                     weeks=weeks, days=days, hours=hours,
-                                     minutes=minutes, seconds=seconds)
+    return from_date - relativedelta(
+        years=years,
+        months=months,
+        weeks=weeks,
+        days=days,
+        hours=hours,
+        minutes=minutes,
+        seconds=seconds,
+    )
+
 
 ## yearsago using Standard library
 # def yearsago(years, from_date=None):
diff --git a/staffeln/conductor/backup.py b/staffeln/conductor/backup.py
index c79c5d9..07b8946 100755
--- a/staffeln/conductor/backup.py
+++ b/staffeln/conductor/backup.py
@@ -16,16 +16,19 @@
 LOG = log.getLogger(__name__)
 
 BackupMapping = collections.namedtuple(
-    "BackupMapping", ["volume_id", "backup_id", "project_id", "instance_id", "backup_completed"]
+    "BackupMapping",
+    ["volume_id", "backup_id", "project_id", "instance_id", "backup_completed"],
 )
 
 QueueMapping = collections.namedtuple(
-    "QueueMapping", ["volume_id", "backup_id", "project_id", "instance_id", "backup_status"]
+    "QueueMapping",
+    ["volume_id", "backup_id", "project_id", "instance_id", "backup_status"],
 )
 
 
 def retry_auth(func):
     """Decorator to reconnect openstack and avoid token rotation"""
+
     def wrapper(self, *args, **kwargs):
         try:
             return func(self, *args, **kwargs)
@@ -34,6 +37,7 @@
                 LOG.warn(_("Token has been expired or rotated!"))
                 self.refresh_openstacksdk()
                 return func(self, *args, **kwargs)
+
     return wrapper
 
 
@@ -86,7 +90,10 @@
             if not CONF.conductor.backup_metadata_key in metadata:
                 return False
 
-            return metadata[CONF.conductor.backup_metadata_key].lower() == constants.BACKUP_ENABLED_KEY
+            return (
+                metadata[CONF.conductor.backup_metadata_key].lower()
+                == constants.BACKUP_ENABLED_KEY
+            )
         else:
             return True
 
@@ -94,10 +101,14 @@
     def filter_by_volume_status(self, volume_id, project_id):
         try:
             volume = self.openstacksdk.get_volume(volume_id, project_id)
-            if volume == None: return False
-            res = volume['status'] in ("available", "in-use")
+            if volume == None:
+                return False
+            res = volume["status"] in ("available", "in-use")
             if not res:
-                reason = _("Volume %s is not backed because it is in %s status" % (volume_id, volume['status']))
+                reason = _(
+                    "Volume %s is not backed because it is in %s status"
+                    % (volume_id, volume["status"])
+                )
                 LOG.info(reason)
                 self.result.add_failed_backup(project_id, volume_id, reason)
             return res
@@ -112,17 +123,18 @@
             reason = _("Cancel backup %s because of timeout." % task.backup_id)
             LOG.info(reason)
 
-            if project_id not in self.project_list: self.process_non_existing_backup(task)
+            if project_id not in self.project_list:
+                self.process_non_existing_backup(task)
             self.openstacksdk.set_project(self.project_list[project_id])
             backup = self.openstacksdk.get_backup(task.backup_id)
-            if backup == None: return task.delete_queue()
+            if backup == None:
+                return task.delete_queue()
             self.openstacksdk.delete_backup(task.backup_id, force=True)
             task.delete_queue()
             self.result.add_failed_backup(task.project_id, task.volume_id, reason)
 
         except OpenstackSDKException as e:
-            reason = _("Backup %s deletion failed."
-                       "%s" % (task.backup_id, str(e)))
+            reason = _("Backup %s deletion failed." "%s" % (task.backup_id, str(e)))
             LOG.info(reason)
             # remove from the queue table
             task.delete_queue()
@@ -133,8 +145,13 @@
         try:
             backup = self.openstacksdk.get_backup(backup_object.backup_id)
             if backup == None:
-                LOG.info(_("Backup %s is not existing in Openstack."
-                           "Or cinder-backup is not existing in the cloud." % backup_object.backup_id))
+                LOG.info(
+                    _(
+                        "Backup %s is not existing in Openstack."
+                        "Or cinder-backup is not existing in the cloud."
+                        % backup_object.backup_id
+                    )
+                )
                 return backup_object.delete_backup()
             if backup["status"] in ("available"):
                 self.openstacksdk.delete_backup(backup_object.backup_id)
@@ -146,13 +163,17 @@
                 #  backup table so user can delete it on Horizon.
                 backup_object.delete_backup()
             else:  # "deleting", "restoring"
-                LOG.info(_("Rotation for the backup %s is skipped in this cycle "
-                           "because it is in %s status") % (backup_object.backup_id, backup["status"]))
+                LOG.info(
+                    _(
+                        "Rotation for the backup %s is skipped in this cycle "
+                        "because it is in %s status"
+                    )
+                    % (backup_object.backup_id, backup["status"])
+                )
 
         except OpenstackSDKException as e:
             LOG.info(
-                _("Backup %s deletion failed." "%s" % (backup_object.backup_id,
-                                                       str(e)))
+                _("Backup %s deletion failed." "%s" % (backup_object.backup_id, str(e)))
             )
             # TODO(Alex): Add it into the notification queue
             # remove from the backup table
@@ -167,11 +188,17 @@
                 backup_object.delete_backup()
 
             self.openstacksdk.set_project(self.project_list[project_id])
-            backup = self.openstacksdk.get_backup(uuid=backup_object.backup_id,
-                                                  project_id=project_id)
+            backup = self.openstacksdk.get_backup(
+                uuid=backup_object.backup_id, project_id=project_id
+            )
             if backup == None:
-                LOG.info(_("Backup %s is not existing in Openstack."
-                           "Or cinder-backup is not existing in the cloud." % backup_object.backup_id))
+                LOG.info(
+                    _(
+                        "Backup %s is not existing in Openstack."
+                        "Or cinder-backup is not existing in the cloud."
+                        % backup_object.backup_id
+                    )
+                )
                 return backup_object.delete_backup()
 
             self.openstacksdk.delete_backup(uuid=backup_object.backup_id)
@@ -179,8 +206,7 @@
 
         except OpenstackSDKException as e:
             LOG.info(
-                _("Backup %s deletion failed." "%s" % (backup_object.backup_id,
-                                                       str(e)))
+                _("Backup %s deletion failed." "%s" % (backup_object.backup_id, str(e)))
             )
 
             # TODO(Alex): Add it into the notification queue
@@ -206,16 +232,22 @@
             try:
                 servers = self.openstacksdk.get_servers(project_id=project.id)
             except OpenstackHttpException as ex:
-                LOG.warn(_("Failed to list servers in project %s. %s"
-                           % (project.id, str(ex))))
+                LOG.warn(
+                    _(
+                        "Failed to list servers in project %s. %s"
+                        % (project.id, str(ex))
+                    )
+                )
                 continue
             for server in servers:
-                if not self.filter_by_server_metadata(server.metadata): continue
+                if not self.filter_by_server_metadata(server.metadata):
+                    continue
                 if empty_project:
                     empty_project = False
                     self.result.add_project(project.id, project.name)
                 for volume in server.attached_volumes:
-                    if not self.filter_by_volume_status(volume["id"], project.id): continue
+                    if not self.filter_by_volume_status(volume["id"], project.id):
+                        continue
                     queues_map.append(
                         QueueMapping(
                             project_id=project.id,
@@ -250,21 +282,29 @@
             try:
                 # NOTE(Alex): no need to wait because we have a cycle time out
                 if project_id not in self.project_list:
-                    LOG.warn(_("Project ID %s is not existing in project list"
-                               % project_id))
+                    LOG.warn(
+                        _("Project ID %s is not existing in project list" % project_id)
+                    )
                     self.process_non_existing_backup(queue)
                     return
                 self.openstacksdk.set_project(self.project_list[project_id])
-                LOG.info(_("Backup for volume %s creating in project %s"
-                           % (queue.volume_id, project_id)))
-                volume_backup = self.openstacksdk.create_backup(volume_id=queue.volume_id,
-                                                                project_id=project_id)
+                LOG.info(
+                    _(
+                        "Backup for volume %s creating in project %s"
+                        % (queue.volume_id, project_id)
+                    )
+                )
+                volume_backup = self.openstacksdk.create_backup(
+                    volume_id=queue.volume_id, project_id=project_id
+                )
                 queue.backup_id = volume_backup.id
                 queue.backup_status = constants.BACKUP_WIP
                 queue.save()
             except OpenstackSDKException as error:
-                reason = _("Backup creation for the volume %s failled. %s"
-                           % (queue.volume_id, str(error)))
+                reason = _(
+                    "Backup creation for the volume %s failled. %s"
+                    % (queue.volume_id, str(error))
+                )
                 LOG.info(reason)
                 self.result.add_failed_backup(project_id, queue.volume_id, reason)
                 parsed = parse.parse("Error in creating volume backup {id}", str(error))
@@ -274,8 +314,10 @@
                 queue.save()
             # Added extra exception as OpenstackSDKException does not handle the keystone unauthourized issue.
             except Exception as error:
-                reason = _("Backup creation for the volume %s failled. %s"
-                           % (queue.volume_id, str(error)))
+                reason = _(
+                    "Backup creation for the volume %s failled. %s"
+                    % (queue.volume_id, str(error))
+                )
                 LOG.error(reason)
                 self.result.add_failed_backup(project_id, queue.volume_id, reason)
                 parsed = parse.parse("Error in creating volume backup {id}", str(error))
@@ -291,8 +333,9 @@
     # backup gen was not created
     def process_pre_failed_backup(self, task):
         # 1.notify via email
-        reason = _("The backup creation for the volume %s was prefailed."
-                   % task.volume_id)
+        reason = _(
+            "The backup creation for the volume %s was prefailed." % task.volume_id
+        )
         self.result.add_failed_backup(task.project_id, task.volume_id, reason)
         # LOG.error(reason)
         # 2. remove failed task from the task queue
@@ -344,13 +387,16 @@
         if queue.backup_id == "NULL":
             self.process_pre_failed_backup(queue)
             return
-        if project_id not in self.project_list: self.process_non_existing_backup(queue)
+        if project_id not in self.project_list:
+            self.process_non_existing_backup(queue)
         self.openstacksdk.set_project(self.project_list[project_id])
         backup_gen = self.openstacksdk.get_backup(queue.backup_id)
 
         if backup_gen == None:
             # TODO(Alex): need to check when it is none
-            LOG.info(_("[Beta] Backup status of %s is returning none." % (queue.backup_id)))
+            LOG.info(
+                _("[Beta] Backup status of %s is returning none." % (queue.backup_id))
+            )
             self.process_non_existing_backup(queue)
             return
         if backup_gen.status == "error":
@@ -362,7 +408,6 @@
         else:  # "deleting", "restoring", "error_restoring" status
             self.process_using_backup(queue)
 
-
     def _volume_backup(self, task):
         # matching_backups = [
         #     g for g in self.available_backups if g.backup_id == task.backup_id
diff --git a/staffeln/conductor/manager.py b/staffeln/conductor/manager.py
index 5388df5..e885043 100755
--- a/staffeln/conductor/manager.py
+++ b/staffeln/conductor/manager.py
@@ -44,7 +44,7 @@
         self.cycle_start_time = xtime.get_current_time()
 
         # loop - take care of backup result while timeout
-        while (1):
+        while 1:
             queues_started = self.controller.get_queues(
                 filters={"backup_status": constants.BACKUP_WIP}
             )
@@ -53,21 +53,31 @@
                 break
             if not self._backup_cycle_timeout():  # time in
                 LOG.info(_("cycle timein"))
-                for queue in queues_started: self.controller.check_volume_backup_status(queue)
+                for queue in queues_started:
+                    self.controller.check_volume_backup_status(queue)
             else:  # time out
                 LOG.info(_("cycle timeout"))
-                for queue in queues_started: self.controller.hard_cancel_backup_task(queue)
+                for queue in queues_started:
+                    self.controller.hard_cancel_backup_task(queue)
                 break
             time.sleep(constants.BACKUP_RESULT_CHECK_INTERVAL)
 
     # if the backup cycle timeout, then return True
     def _backup_cycle_timeout(self):
-        time_delta_dict = xtime.parse_timedelta_string(CONF.conductor.backup_cycle_timout)
+        time_delta_dict = xtime.parse_timedelta_string(
+            CONF.conductor.backup_cycle_timout
+        )
 
         if time_delta_dict == None:
-            LOG.info(_("Recycle timeout format is invalid. "
-                       "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."))
-            time_delta_dict = xtime.parse_timedelta_string(constants.DEFAULT_BACKUP_CYCLE_TIMEOUT)
+            LOG.info(
+                _(
+                    "Recycle timeout format is invalid. "
+                    "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."
+                )
+            )
+            time_delta_dict = xtime.parse_timedelta_string(
+                constants.DEFAULT_BACKUP_CYCLE_TIMEOUT
+            )
         rto = xtime.timeago(
             years=time_delta_dict["years"],
             months=time_delta_dict["months"],
@@ -119,11 +129,14 @@
         periodic_callables = [
             (backup_tasks, (), {}),
         ]
-        periodic_worker = periodics.PeriodicWorker(periodic_callables, schedule_strategy="last_finished")
+        periodic_worker = periodics.PeriodicWorker(
+            periodic_callables, schedule_strategy="last_finished"
+        )
         periodic_thread = threading.Thread(target=periodic_worker.start)
         periodic_thread.daemon = True
         periodic_thread.start()
 
+
 class RotationManager(cotyledon.Service):
     name = "Staffeln conductor rotation controller"
 
@@ -147,8 +160,11 @@
 
     def get_backup_list(self):
         threshold_strtime = self.get_threshold_strtime()
-        if threshold_strtime == None: return False
-        self.backup_list = self.controller.get_backups(filters={"created_at__lt": threshold_strtime})
+        if threshold_strtime == None:
+            return False
+        self.backup_list = self.controller.get_backups(
+            filters={"created_at__lt": threshold_strtime}
+        )
         return True
 
     def remove_backups(self):
@@ -163,15 +179,19 @@
         def rotation_tasks():
             self.controller.refresh_openstacksdk()
             # 1. get the list of backups to remove based on the retention time
-            if not self.get_backup_list(): return
+            if not self.get_backup_list():
+                return
             # 2. get project list
             self.controller.update_project_list()
             # 3. remove the backups
             self.remove_backups()
+
         periodic_callables = [
             (rotation_tasks, (), {}),
         ]
-        periodic_worker = periodics.PeriodicWorker(periodic_callables, schedule_strategy="last_finished")
+        periodic_worker = periodics.PeriodicWorker(
+            periodic_callables, schedule_strategy="last_finished"
+        )
         periodic_thread = threading.Thread(target=periodic_worker.start)
         periodic_thread.daemon = True
         periodic_thread.start()
@@ -180,8 +200,12 @@
     def get_threshold_strtime(self):
         time_delta_dict = xtime.parse_timedelta_string(CONF.conductor.retention_time)
         if time_delta_dict == None:
-            LOG.info(_("Retention time format is invalid. "
-                       "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."))
+            LOG.info(
+                _(
+                    "Retention time format is invalid. "
+                    "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."
+                )
+            )
             return None
 
         res = xtime.timeago(
diff --git a/staffeln/conductor/result.py b/staffeln/conductor/result.py
index b16bcc6..3a6d640 100644
--- a/staffeln/conductor/result.py
+++ b/staffeln/conductor/result.py
@@ -16,7 +16,6 @@
 
 
 class BackupResult(object):
-
     def __init__(self):
         pass
 
@@ -27,11 +26,9 @@
         self.failed_backup_list = {}
 
     def add_project(self, id, name):
-        if id in self.success_backup_list: return
-        self.project_list.append({
-            "name": name,
-            "id": id
-        })
+        if id in self.success_backup_list:
+            return
+        self.project_list.append({"name": name, "id": id})
         self.success_backup_list[id] = []
         self.failed_backup_list[id] = []
 
@@ -39,24 +36,29 @@
         if not project_id in self.success_backup_list:
             LOG.error(_("Not registered project is reported for backup result."))
             return
-        self.success_backup_list[project_id].append({
-            "volume_id": volume_id,
-            "backup_id": backup_id,
-        })
+        self.success_backup_list[project_id].append(
+            {
+                "volume_id": volume_id,
+                "backup_id": backup_id,
+            }
+        )
 
     def add_failed_backup(self, project_id, volume_id, reason):
         if not project_id in self.failed_backup_list:
             LOG.error(_("Not registered project is reported for backup result."))
             return
-        self.failed_backup_list[project_id].append({
-            "volume_id": volume_id,
-            "reason": reason,
-        })
+        self.failed_backup_list[project_id].append(
+            {
+                "volume_id": volume_id,
+                "reason": reason,
+            }
+        )
 
     def send_result_email(self):
         subject = "Backup result"
         try:
-            if len(CONF.notification.receiver) == 0: return
+            if len(CONF.notification.receiver) == 0:
+                return
             email.send(
                 src_email=CONF.notification.sender_email,
                 src_pwd=CONF.notification.sender_pwd,
@@ -68,7 +70,12 @@
             )
             LOG.info(_("Backup result email sent"))
         except Exception as e:
-            LOG.error(_("Backup result email send failed. Please check email configuration. %s" % (str(e))))
+            LOG.error(
+                _(
+                    "Backup result email send failed. Please check email configuration. %s"
+                    % (str(e))
+                )
+            )
 
     def publish(self):
         # 1. get quota
@@ -78,16 +85,17 @@
         for project in self.project_list:
             quota = backup.Backup().get_backup_quota(project["id"])
 
-            html += "<h3>Project: ${PROJECT}</h3><br>" \
-                    "<h3>Quota Usage</h3><br>" \
-                    "<h4>Limit: ${QUOTA_LIMIT}, In Use: ${QUOTA_IN_USE}, Reserved: ${QUOTA_RESERVED}</h4><br>" \
-                    "<h3>Success List</h3><br>" \
-                    "<h4>${SUCCESS_VOLUME_LIST}</h4><br>" \
-                    "<h3>Failed List</h3><br>" \
-                    "<h4>${FAILED_VOLUME_LIST}</h4><br>"
+            html += (
+                "<h3>Project: ${PROJECT}</h3><br>"
+                "<h3>Quota Usage</h3><br>"
+                "<h4>Limit: ${QUOTA_LIMIT}, In Use: ${QUOTA_IN_USE}, Reserved: ${QUOTA_RESERVED}</h4><br>"
+                "<h3>Success List</h3><br>"
+                "<h4>${SUCCESS_VOLUME_LIST}</h4><br>"
+                "<h3>Failed List</h3><br>"
+                "<h4>${FAILED_VOLUME_LIST}</h4><br>"
+            )
 
             success_volumes = "<br>".join(
-
                 [
                     "Volume ID: %s, Backup ID: %s"
                     % (str(e["volume_id"]), str(e["backup_id"]))
@@ -108,6 +116,7 @@
             html = html.replace("${SUCCESS_VOLUME_LIST}", success_volumes)
             html = html.replace("${FAILED_VOLUME_LIST}", failed_volumes)
             html = html.replace("${PROJECT}", project["name"])
-        if html == "": return
+        if html == "":
+            return
         self.content += html
         self.send_result_email()
diff --git a/staffeln/conf/conductor.py b/staffeln/conf/conductor.py
index 69f7fe2..cb665d5 100755
--- a/staffeln/conf/conductor.py
+++ b/staffeln/conf/conductor.py
@@ -12,8 +12,10 @@
     cfg.IntOpt(
         "backup_workers",
         default=1,
-        help=_("The maximum number of backup processes to "
-               "fork and run. Default to number of CPUs on the host."),
+        help=_(
+            "The maximum number of backup processes to "
+            "fork and run. Default to number of CPUs on the host."
+        ),
     ),
     cfg.IntOpt(
         "backup_service_period",
@@ -23,10 +25,12 @@
     ),
     cfg.StrOpt(
         "backup_cycle_timout",
-        regex=r'((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?',
+        regex=r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?",
         default=constants.DEFAULT_BACKUP_CYCLE_TIMEOUT,
-        help=_("The duration while the backup cycle waits backups."
-               "<YEARS>y<MONTHS>mon<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."),
+        help=_(
+            "The duration while the backup cycle waits backups."
+            "<YEARS>y<MONTHS>mon<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."
+        ),
     ),
     cfg.StrOpt(
         "backup_metadata_key",
@@ -38,8 +42,10 @@
     cfg.IntOpt(
         "rotation_workers",
         default=1,
-        help=_("The maximum number of rotation processes to "
-               "fork and run. Default to number of CPUs on the host."),
+        help=_(
+            "The maximum number of rotation processes to "
+            "fork and run. Default to number of CPUs on the host."
+        ),
     ),
     cfg.IntOpt(
         "retention_service_period",
@@ -50,15 +56,19 @@
     cfg.IntOpt(
         "rotation_workers",
         default=1,
-        help=_("The maximum number of rotation processes to "
-               "fork and run. Default to number of CPUs on the host."),
+        help=_(
+            "The maximum number of rotation processes to "
+            "fork and run. Default to number of CPUs on the host."
+        ),
     ),
     cfg.StrOpt(
         "retention_time",
-        regex=r'((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?',
+        regex=r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?",
         default="2w3d",
-        help=_("The time of retention period, the for mat is "
-               "<YEARS>y<MONTHS>mon<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."),
+        help=_(
+            "The time of retention period, the for mat is "
+            "<YEARS>y<MONTHS>mon<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."
+        ),
     ),
 ]
 
diff --git a/staffeln/db/api.py b/staffeln/db/api.py
index db0255f..029ad11 100644
--- a/staffeln/db/api.py
+++ b/staffeln/db/api.py
@@ -12,6 +12,5 @@
     """Return a DB API instance."""
     return IMPL
 
-
-# class BaseConnection(object, metaclass=abc.ABCMeta):
+    # class BaseConnection(object, metaclass=abc.ABCMeta):
     """Base class for storage system connections."""
diff --git a/staffeln/db/migration.py b/staffeln/db/migration.py
index 176d66a..24e03ee 100644
--- a/staffeln/db/migration.py
+++ b/staffeln/db/migration.py
@@ -12,8 +12,9 @@
 def get_backend():
     global _IMPL
     if not _IMPL:
-        _IMPL = driver.DriverManager("staffeln.database.migration_backend",
-                                     CONF.database.backend).driver
+        _IMPL = driver.DriverManager(
+            "staffeln.database.migration_backend", CONF.database.backend
+        ).driver
     return _IMPL
 
 
diff --git a/staffeln/db/sqlalchemy/api.py b/staffeln/db/sqlalchemy/api.py
index 0148c3d..c777c19 100644
--- a/staffeln/db/sqlalchemy/api.py
+++ b/staffeln/db/sqlalchemy/api.py
@@ -109,14 +109,13 @@
         if filters is None:
             filters = {}
 
-
         plain_fields = [
             "volume_id",
             "backup_id",
             "project_id",
             "backup_completed",
             "instance_id",
-            "created_at"
+            "created_at",
         ]
 
         return self._add_filters(
@@ -317,7 +316,6 @@
         except:
             LOG.error("Queue Not found.")
 
-
     def get_backup_by_backup_id(self, context, backup_id):
         """Get the column from the backup_data with matching backup_id"""
 
@@ -336,7 +334,6 @@
         except:
             LOG.error("Backup resource not found.")
 
-
     def soft_delete_backup(self, id):
         try:
             return self._soft_delete(models.Backup_data, id)
diff --git a/staffeln/i18n.py b/staffeln/i18n.py
index 462c91c..09fe8aa 100755
--- a/staffeln/i18n.py
+++ b/staffeln/i18n.py
@@ -4,7 +4,7 @@
 
 import oslo_i18n
 
-DOMAIN = 'staffeln'
+DOMAIN = "staffeln"
 
 _translators = oslo_i18n.TranslatorFactory(domain=DOMAIN)
 
diff --git a/staffeln/objects/__init__.py b/staffeln/objects/__init__.py
index 4f7ca56..4a5adfd 100755
--- a/staffeln/objects/__init__.py
+++ b/staffeln/objects/__init__.py
@@ -1,6 +1,7 @@
 from .queue import Queue
 from .volume import Volume
+
 # from volume import Volume
 def register_all():
-    __import__('staffeln.objects.volume')
-    __import__('staffeln.objects.queue')
+    __import__("staffeln.objects.volume")
+    __import__("staffeln.objects.queue")
diff --git a/staffeln/objects/volume.py b/staffeln/objects/volume.py
index ce300af..1216c64 100644
--- a/staffeln/objects/volume.py
+++ b/staffeln/objects/volume.py
@@ -83,4 +83,3 @@
         else:
             backup = cls._from_db_object(cls(context), db_backup)
             return backup
-          
\ No newline at end of file
diff --git a/staffeln/tests/test_staffeln.py b/staffeln/tests/test_staffeln.py
index a8b6e32..6c7c5f3 100755
--- a/staffeln/tests/test_staffeln.py
+++ b/staffeln/tests/test_staffeln.py
@@ -23,6 +23,5 @@
 
 
 class TestStaffeln(base.TestCase):
-
     def test_something(self):
         pass
diff --git a/staffeln/version.py b/staffeln/version.py
index 0f9e8d2..1ef8d77 100755
--- a/staffeln/version.py
+++ b/staffeln/version.py
@@ -1,5 +1,5 @@
 import pbr.version
 
 
-version_info = pbr.version.VersionInfo('staffeln')
+version_info = pbr.version.VersionInfo("staffeln")
 version_string = version_info.version_string