code: def _keys(self, pattern):
          
          result = []
          for client in self.redis_clients:
              result.extend(list(client.scan_iter(match=pattern)))
          return result
docs: Execute the KEYS command on all Redis shards.
  
          Args:
              pattern: The KEYS pattern to query.
  
          Returns:
              The concatenated list of results from all shards.