"""Base classes for storage engines"""
from oslo_config import cfg
from oslo_db import api as db_api

_BACKEND_MAPPING = {"sqlalchemy": "staffeln.db.sqlalchemy.api"}
IMPL = db_api.DBAPI.from_config(cfg.CONF, backend_mapping=_BACKEND_MAPPING, lazy=True)


def get_instance():
    """Return a DB API instance."""
    return IMPL