diff --git a/python/message.c b/python/message.c
index 9921081..77e4a15 100644
--- a/python/message.c
+++ b/python/message.c
@@ -925,7 +925,7 @@
     field_desc = NULL;
     py_val = NULL;
     if (!tuple) goto err;
-    if (!PyList_Append(list, tuple)) goto err;
+    if (PyList_Append(list, tuple)) goto err;
     Py_DECREF(tuple);
     tuple = NULL;
   }