code: def get_rank(self, member, reverse=False, pipe=None):
          
          pipe = self.redis if pipe is None else pipe
          method = getattr(pipe, 'zrevrank' if reverse else 'zrank')
          rank = method(self.key, self._pickle(member))
  
          return rank
docs: Return the rank of *member* in the collection.
          By default, the member with the lowest score has rank 0.
          If *reverse* is ``True``, the member with the highest score has rank 0.