Fixed return of parent_id in Message wrapper

Author: Sergey Dmitrenko

mmpy_bot/wrappers.py

@@ -52,7 +52,7 @@ def mentions(self):
 
     @cached_property
     def parent_id(self):
-        return self.body["data"]["post"]["parent_id"]
+        return self.body["data"]["post"].get("parent_id", "").strip()
 
     @cached_property
     def reply_id(self):