docs: def qlist(self, name_start, name_end, limit):
          """
          Return a list of the top ``limit`` keys between ``name_start`` and
          ``name_end``  in ascending order
  
          .. note:: The range is (``name_start``, ``name_end``]. ``name_start``
             isn't in the range, but ``name_end`` is.
  
          :param string name_start: The lower bound(not included) of keys to be
           returned, empty string ``''`` means -inf
          :param string name_end: The upper bound(included) of keys to be
           returned, empty string ``''`` means +inf
          :param int limit: number of elements will be returned.
          :return: a list of keys
          :rtype: list
  
          >>> ssdb.qlist('queue_1', 'queue_2', 10)
          ['queue_2']
          >>> ssdb.qlist('queue_', 'queue_2', 10)
          ['queue_1', 'queue_2']
          >>> ssdb.qlist('z', '', 10)
          []        
          """
          limit = get_positive_integer("limit", limit)
          return self.execute_command('qlist', name_start, name_end, limit)