fix an embarrassing python programming error

federation/entities/activitypub/models.py

@@ -1303,7 +1303,11 @@ def extract_and_validate(entity):
         entity.extract_mentions()
 
 
-def extract_replies(replies, objs=[], visited=[]):
+def extract_replies(replies):
+    objs = []
+    visited = []
+
+    def walk_reply_collection(replies):
         items = getattr(replies, 'items', [])
         if items and not isinstance(items, list): items = [items]
         for obj in items:
@@ -1316,14 +1320,15 @@ def extract_replies(replies, objs=[], visited=[]):
                     continue
             elif not isinstance(obj, str): continue
             objs.append(obj)
-    if hasattr(replies, 'next_'):
-        if replies.next_ and (replies.id != replies.next_) and (replies.next_ not in visited):
+        if getattr(replies, 'next_', None):
+            if (replies.id != replies.next_) and (replies.next_ not in visited):
                 resp = retrieve_and_parse_document(replies.next_)
                 if resp:
                     visited.append(replies.next_)
-                return objs + extract_replies(resp, objs, visited)
-        return []
-    return []
+                    walk_reply_collection(resp)
+
+    walk_reply_collection(replies)
+    return objs
 
 
 def element_to_objects(element: Union[Dict, Object]) -> List: