--- a/mercurial/parsers.c	Wed Oct 05 13:45:22 2016 +0200
+++ b/mercurial/parsers.c	Sat Oct 08 17:51:29 2016 +0200
@@ -2880,7 +2880,7 @@
 	PyObject *mod;
 
 	if (check_python_version() == -1)
-		return;
+		return NULL;
 	mod = PyModule_Create(&parsers_module);
 	module_init(mod);
 	return mod;