def ping(self, user, text = None):
        """
        Measure round-trip delay to another IRC client.
        """
        if self._pings is None:
            self._pings = {}

        if text is None:
            chars = string.letters + string.digits + string.punctuation
            key = ''.join([random.choice(chars) for i in range(12)])
        else:
            key = str(text)
        self._pings[(user, key)] = time.time()
        self.ctcpMakeQuery(user, [('PING', key)])

        if len(self._pings) > self._MAX_PINGRING:
            # Remove some of the oldest entries.
            byValue = [(v, k) for (k, v) in self._pings.items()]
            byValue.sort()
            excess = self._MAX_PINGRING - len(self._pings)
            for i in xrange(excess):
                del self._pings[byValue[i][1]]
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/words/protocols/irc.py/IRCClient.ping/original