def zadd(self, key, *item_tuples, **kwargs):
        if not kwargs and len(item_tuples) == 2 and \
           isinstance(item_tuples[0], basestring):
            self._send('ZADD', key, item_tuples[1], item_tuples[0])
        elif not kwargs:
            self._send('ZADD', key, *item_tuples)
        elif 'member' in kwargs and 'score' in kwargs:
            score, member = item_tuples
            self._send('ZADD', key, kwargs['score'], kwargs['member'])
        else:
            raise exceptions.InvalidCommand('Need arguments for ZADD')
        return self.getResponse()
Converts given lat/lon in WGS84 Datum to XY in Spherical Mercator EPSG:900913
dataset/ETHPy150Open deldotdr/txRedis/txredis/client.py/RedisClient.zadd--crossover with--dataset/ETHPy150Open Ecotrust/create-utfgrids/globalmaptiles.py/GlobalMercator.LatLonToMeters