code: def __getitem__(self, index: int) -> Tuple[TimeSeries, TimeSeries]:
      ts, ctx_window, tgt_window = self._fetch(index)
      ctx = ts[ctx_window]
      tgt = ts[tgt_window]
      return ctx, tgt
  
file_path: gluonts/src/gluonts/nursery/daf/tslib/dataset/forecasting.py
imports: from __future__ import annotations
  from typing import List, Tuple, Dict, Optional
  import numpy
  from tqdm import tqdm
  from .timeseries import TimeSeries, TimeSeriesCorpus
  from .windows import WindowsDataset
label_desc: Use image node_id 2 for calling the ForecastingDataset obj's underlying member method code with example usage: obj.__getitem__(index) and returns: ctx,  tgt