diff --git a/doc/conf.py b/doc/conf.py
index 31d5c2f..0c0d4c6 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -42,7 +42,7 @@ extensions = [
 ]
 
 intersphinx_mapping = {
-    'http://docs.python.org/': None,
+    'http://docs.python.org/': '../debian/python.inv',
     'https://greenlet.readthedocs.io/en/latest/': None,
     'https://zopeevent.readthedocs.io/en/latest/': None,
     'https://zopecomponent.readthedocs.io/en/latest/': None,