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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def on_close(self):
        '''
        Called when client closes this connection. Cleanup
        is done here.
        '''

        if self.id in self.funcserver.websocks:
            self.funcserver.websocks[self.id] = None
            ioloop = tornado.ioloop.IOLoop.instance()
            ioloop.add_callback(lambda: self.funcserver.websocks.pop(self.id, None))

        psession = self.funcserver.pysessions.get(self.pysession_id, None)
        if psession:
            psession['socks'].remove(self.id)
            if not psession['socks']:
                del self.funcserver.pysessions[self.pysession_id]