Return NULL instead of 0 from function with a pointer return value.
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index 76abe1f..d259998 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -842,7 +842,7 @@
             PyErr_Clear();
             PyErr_SetString(PyExc_TypeError,
                             "argument must have 'read' attribute");
-            return 0;
+            return NULL;
         }
     }
     for (;;) {