code: def my_series(request):
      idx = request.param("2021-01-01", freq="1D", periods=3)
      series = pd.Series(np.random.normal(size=3), index=idx)
      return series
  
imports: import io
  from typing import Callable, List, Union
  import pandas
  import numpy
  import pytest
  from gluonts.dataset import pandas
  from gluonts.testutil.equality import assert_recursively_equal
label_desc: Use image node_id 1 for calling a global function with example usage: my_series(request) and returns: series