class_docstr: The interface which has to be implemented for any telnet application.
  An instance of this class has to be passed to `TelnetServer`.
class_docstr_tok: ["The","interface","which","has","to","be","implemented","for","any","telnet","application",".","An","instance","of","this","class","has","to","be","passed","to","`","TelnetServer","`","."]
docstr: Called when a client quits.
docstr_tok: ["Called","when","a","client","quits","."]
code: def client_leaving(self, telnet_connection):
      """
      Called when a client quits.
      """
  
imports: from __future__ import unicode_literals
  from abc import ABCMeta, abstractmethod
  from six import with_metaclass
label_desc: Use image node_id 2 for calling the TelnetApplication obj's underlying member method code with example usage: obj.client_leaving(telnet_connection) without return types