Get the LUSERS information.
        Optional arguments:
        * mask=None - Mask to get LUSERS information of.
        * target=None - Forward the query.

def get_lusers(self, mask=None, target=None):
        """
        Get the LUSERS information.
        Optional arguments:
        * mask=None - Mask to get LUSERS information of.
        * target=None - Forward the query.
        """
        with self.lock:
            if not mask:
                self.send('LUSERS')
            elif not target and mask:
                self.send('LUSERS %s' % mask)
            else:
                self.send('LUSERS %s %s' % (mask, target))
            while self.readable():
                msg = self._recv(expected_replies=('250', '251', '252', \
                                            '254', '255', '265', '266'))
                segments = msg[2].split()
                if msg[0] == '250':
                    self.lusers['HIGHESTCONNECTIONS'] = segments[3]
                    self.lusers['TOTALCONNECTIONS'] = segments[9][1:]
                elif msg[0] == '251':
                    self.lusers['USERS'] = segments[2]
                    self.lusers['INVISIBLE'] = segments[5]
                    self.lusers['SERVERS'] = segments[8]

                elif msg[0] == '252':
                    self.lusers['OPERATORS'] = segments[0]

                elif msg[0] == '254':
                    self.lusers['CHANNELS'] = segments[0]

                elif msg[0] == '255':
                    self.lusers['CLIENTS'] = segments[2]
                    self.lusers['LSERVERS'] = segments[5]

                elif msg[0] == '265':
                    self.lusers['LOCALUSERS'] = segments[3]
                    self.lusers['LOCALMAX'] = segments[5]

                elif msg[0] == '266':
                    self.lusers['GLOBALUSERS'] = segments[3]
                    self.lusers['GLOBALMAX'] = segments[5]
                    break
            return self.lusers