code: def ParseMessage(descriptor, byte_str):
    
    result_class = MakeClass(descriptor)
    new_msg = result_class()
    new_msg.ParseFromString(byte_str)
    return new_msg
docs: Generate a new Message instance from this Descriptor and a byte string.
  
    Args:
      descriptor: Protobuf Descriptor object
      byte_str: Serialized protocol buffer byte string
  
    Returns:
      Newly created protobuf Message object.