--- a/black.toml	Mon Oct 14 12:54:49 2019 -0400
+++ b/black.toml	Mon Oct 14 12:55:40 2019 -0400
@@ -11,6 +11,7 @@
 | mercurial/thirdparty/
 | hgext/fsmonitor/pywatchman/
 | contrib/python-zstandard/
+| contrib/grey.py
 '''
 skip-string-normalization = true
 quiet = true