use NULL not 0
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 38ddb0f..eec9532 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2191,9 +2191,8 @@
         return null_error();
 
     func = PyObject_GetAttrString(o, name);
-    if (func == NULL) {
-        return 0;
-    }
+    if (func == NULL)
+        return NULL;
 
     va_start(va, format);
     retval = callmethod(func, format, va, 0);
@@ -2213,9 +2212,8 @@
         return null_error();
 
     func = _PyObject_GetAttrId(o, name);
-    if (func == NULL) {
-        return 0;
-    }
+    if (func == NULL)
+        return NULL;
 
     va_start(va, format);
     retval = callmethod(func, format, va, 0);
@@ -2235,9 +2233,8 @@
         return null_error();
 
     func = PyObject_GetAttrString(o, name);
-    if (func == NULL) {
-        return 0;
-    }
+    if (func == NULL)
+        return NULL;
     va_start(va, format);
     retval = callmethod(func, format, va, 1);
     va_end(va);