diff --git a/tox.ini b/tox.ini
index 77e3612e..34198fa9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-skipsdist=True
+skipsdist = True
 envlist = cov, flake8
 
 [testenv]
@@ -24,7 +24,7 @@ commands =
     flake8 tests
 
 
-# pytest Configuration
+# Pytest configuration
 [pytest]
 junit_family = xunit2
 testpaths = tests
@@ -32,8 +32,12 @@ filterwarnings =
     ignore:.*'collections'.*'collections.abc'.*:DeprecationWarning
     ignore:Task.all_tasks() is deprecated, use asyncio.all_tasks().*:PendingDeprecationWarning
 
-# Flake8 Configuration
+
+# Flake8 configuration
 [flake8]
 # gettext() adds _() to the global namespace. This lets flake recognize it.
 builtins =
     _,
+
+# https://github.com/psf/black/blob/master/docs/the_black_code_style.md#slices
+extend-ignore = E203