class_docstr: RedisTimeSeries Commands.
docstr: Append GROUPBY REDUCE property to params.
code: def _append_groupby_reduce(
      params: List[str], groupby: Optional[str], reduce: Optional[str]
  ):
      """Append GROUPBY REDUCE property to params."""
      if groupby is not None and reduce is not None:
          params.extend(["GROUPBY", groupby, "REDUCE", reduce.upper()])
  
imports: from typing import Dict, List, Optional, Tuple, Union
  from redis.exceptions import DataError
  from redis.typing import KeyT, Number
label_desc: Use image node_id 22 for calling the TimeSeriesCommands obj's underlying member method code with example usage: obj._append_groupby_reduce(params, groupby, reduce) without return types