code: def test_expanding(self, f, frame):
      g = frame.groupby("A", group_keys=False)
      r = g.expanding()
  
      result = getattr(r, f)()
      msg = "DataFrameGroupBy.apply operated on the grouping columns"
      with tm.assert_produces_warning(FutureWarning, match=msg):
          expected = g.apply(lambda x: getattr(x.expanding(), f)())
      # groupby.apply doesn't drop the grouped-by column
      expected = expected.drop("A", axis=1)
      # GH 39732
      expected_index = MultiIndex.from_arrays([frame["A"], range(40)])
      expected.index = expected_index
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  from pandas import DataFrame, DatetimeIndex, Index, MultiIndex, Series, Timestamp, date_range, to_datetime
  import pandas._testing
  from pandas.api.indexers import BaseIndexer
  from pandas.core.groupby.groupby import get_groupby
label_desc: Use image node_id 2 for calling the TestExpanding obj's underlying member method code with example usage: obj.test_expanding(f, frame) without return types