diff --git a/docs/conf.py b/docs/conf.py
index 019d32f..13d491a 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -39,7 +39,7 @@
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 #
-source_suffix = ['.rst', '.md']
+source_suffix = [".rst", ".md"]
 
 # The master toctree document.
 master_doc = "index"