Remove unused parts
diff --git a/tox.ini b/tox.ini
index 9676ac4..4812539 100755
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py3,pep8
+envlist = py37,pep8
 skipsdist = True
 sitepackages = False
 skip_missing_interpreters = True