code: def add(self, data, id='*', maxlen=None, approximate=True):
          
          return self.database.xadd(self.key, data, id, maxlen, approximate)
docs: Add data to a stream.
  
          :param dict data: data to add to stream
          :param id: identifier for message ('*' to automatically append)
          :param maxlen: maximum length for stream
          :param approximate: allow stream max length to be approximate
          :returns: the added message id.