Index: b/docs/conf.py
===================================================================
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -32,7 +32,7 @@ extensions = [
 ]
 
 intersphinx_mapping = {
-    'python': ('https://docs.python.org/3/', None),
+    'python': ('https://docs.python.org/3/', 'python3.inv'),
 }
 
 # Add any paths that contain templates here, relative to this directory.