python: add error property to messages

python/src/deltachat/message.py

@@ -212,6 +212,11 @@ class Message(object):
                 return email.message_from_bytes(s)
             return email.message_from_string(s)
 
+    @property
+    def error(self):
+        """Error message"""
+        return from_dc_charpointer(lib.dc_msg_get_error(self._dc_msg))
+
     @property
     def chat(self):
         """chat this message was posted in.