diff --git a/doc/source/conf.py b/doc/source/conf.py
index 7a37e87a5073..c96da6f7c34b 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -197,6 +197,7 @@ def monkey_patch_blockdiag():
     from codecs import getreader
 
     from blockdiag.imagedraw import textfolder
+    from blockdiag.utils import compat  # noqa
 
     # oh, blockdiag. Let's undo the mess you made.
     codecs.getreader = getreader