def reply_privately(*strings)
      private_source = source.clone
      private_source.private_message!
      @robot.send_messages(private_source, *strings)
    end
def reply_privately(*strings)
      private_source = source.clone
      private_source.private_message!
      @robot.send_messages(private_source, *strings)
    end
Replies by sending the given strings back to the user who sent the
 message directly, even if the message was sent in a room.
 @param strings [String, Array<String>] The strings to send back.
 @return [void]