code: def CopyFrom(self, other_msg):
      
      if self is other_msg:
        return
      self.Clear()
      self.MergeFrom(other_msg)
docs: Copies the content of the specified message into the current message.
  
      The method clears the current message and then merges the specified
      message using MergeFrom.
  
      Args:
        other_msg: Message to copy into the current one.