code: def ts_transform(
      series: TimeSeries, params: Mapping[str, Any]
  ) -> TimeSeries:
      return series.window_transform(**params["fixed"])
  
imports: from typing import Any, List, Mapping, Optional, Union
  from darts.dataprocessing.transformers import BaseDataTransformer
  from darts.logging import get_logger
  from darts.timeseries import TimeSeries
label_desc: Use image node_id 2 for calling the WindowTransformer obj's underlying member method code with example usage: obj.ts_transform(series, params) and returns: series