code: def test_count_groupby_column_with_nan_in_groupby_column(self):
      # https://github.com/pandas-dev/pandas/issues/32841
      df = DataFrame({"A": [1, 1, 1, 1, 1], "B": [5, 4, np.nan, 3, 0]})
      res = df.groupby(["B"]).count()
      expected = DataFrame(
          index=Index([0.0, 3.0, 4.0, 5.0], name="B"),
          data={"A": [1, 1, 1, 1]},
      )
      tm.assert_frame_equal(expected, res)
  
imports: from itertools import product
  from string import ascii_lowercase
  import numpy
  import pytest
  from pandas import DataFrame, Index, MultiIndex, Period, Series, Timedelta, Timestamp, date_range
  import pandas._testing
label_desc: Use image node_id 20 for calling the TestCounting obj's underlying member method code with example usage: obj.test_count_groupby_column_with_nan_in_groupby_column() without return types