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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 quit(self):
 """ Send LMTP QUIT command, read the server response and disconnect. """

        self._send('QUIT\r\n')
        resp = self._read()
        if not resp.startswith('221'):
            logger.warning('Unexpected server response at QUIT: ' + resp)
        self._socket.close()
        self._socket = None
        self._recipients = []
        self.results = {}