code: def flat_data(rng, request):
      index = pd.RangeIndex(10, 30, name="t")
      series = pd.Series(rng.normal(size=20), index, name="s")
      if request.param == "series":
          data = series
      elif request.param == "array":
          data = series.to_numpy()
      elif request.param == "list":
          data = series.to_list()
      return data
  
imports: import numpy
  import pandas
  import pytest
label_desc: Use image node_id 9 for calling a global function with example usage: flat_data(rng, request) and returns: data