diff --git a/Doc/tools/refcounts.py b/Doc/tools/refcounts.py
index 6056328..90f47d0 100644
--- a/Doc/tools/refcounts.py
+++ b/Doc/tools/refcounts.py
@@ -33,7 +33,9 @@
             continue
         parts = string.split(line, ":", 4)
         function, type, arg, refcount, comment = parts
-        if refcount:
+        if refcount == "null":
+            refcount = None
+        elif refcount:
             refcount = int(refcount)
         else:
             refcount = None