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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 start_multiplex_socket(self, streams, callback):
 """Start a multiplexed socket using a list of socket names. User stream sockets can not be included. Symbols in socket name must be lowercase i.e bnbbtc@aggTrade, neobtc@ticker Combined stream events are wrapped as follows: {"stream":"<streamName>","data":<rawPayload>} https://github.com/binance-exchange/binance-official-api-docs/blob/master/web-socket-streams.md :param streams: list of stream names in lower case :type streams: list :param callback: callback function to handle messages :type callback: function :returns: connection key string if successful, False otherwise Message Format - see Binance API docs for all types """

        stream_path = 'streams={}'.format('/'.join(streams))
        return self._start_socket(stream_path, callback, 'stream?')