code: def test_expanding_corr_cov(self, f, frame):
      g = frame.groupby("A")
      r = g.expanding()
  
      result = getattr(r, f)(frame)
  
      def func_0(x):
          return getattr(x.expanding(), f)(frame)
  
      msg = "DataFrameGroupBy.apply operated on the grouping columns"
      with tm.assert_produces_warning(FutureWarning, match=msg):
          expected = g.apply(func_0)
      # GH 39591: groupby.apply returns 1 instead of nan for windows
      # with all nan values
      null_idx = list(range(20, 61)) + list(range(72, 113))
      expected.iloc[null_idx, 1] = np.nan
      # GH 39591: The grouped column should be all np.nan
      # (groupby.apply inserts 0s for cov)
      expected["A"] = np.nan
      tm.assert_frame_equal(result, expected)
  
      result = getattr(r.B, f)(pairwise=True)
  
      def func_1(x):
          return getattr(x.B.expanding(), f)(pairwise=True)
  
      msg = "DataFrameGroupBy.apply operated on the grouping columns"
      with tm.assert_produces_warning(FutureWarning, match=msg):
          expected = g.apply(func_1)
      tm.assert_series_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 5 for calling the TestExpanding obj's underlying member method code with example usage: obj.test_expanding_corr_cov(f, frame) and returns: getattr, getattr