diff --git a/docs/advanced_tools/advanced_tools.py b/docs/advanced_tools/advanced_tools.py
index 11deade6b..5929fe270 100644
--- a/docs/advanced_tools/advanced_tools.py
+++ b/docs/advanced_tools/advanced_tools.py
@@ -1,3 +1,4 @@
+"""
 Advanced tools
 ===============
 
@@ -7,4 +8,5 @@
 Subtitles
 ----------
 
-Credits 
\ No newline at end of file
+Credits
+"""