code: def test_cython_fail_agg():
      dr = bdate_range("1/1/2000", periods=50)
      ts = Series(["A", "B", "C", "D", "E"] * 10, index=dr)
  
      grouped = ts.groupby(lambda x: x.month)
      summed = grouped.sum()
      msg = "using SeriesGroupBy.sum"
      with tm.assert_produces_warning(FutureWarning, match=msg):
          # GH#53425
          expected = grouped.agg(np.sum)
      tm.assert_series_equal(summed, expected)
  
imports: import numpy
  import pytest
  from pandas.core.dtypes.common import is_float_dtype, is_integer_dtype
  import pandas
  from pandas import DataFrame, Index, NaT, Series, Timedelta, Timestamp, bdate_range
  import pandas._testing
  import pandas.core.common
label_desc: Use image node_id 7 for calling a global function with example usage: test_cython_fail_agg() without return types