code: def test_filter_dropna_with_empty_groups():
      # GH 10780
      data = Series(
          np.random.default_rng(2).random(9),
          index=np.repeat([1, 2, 3], 3),
      )
      grouped = data.groupby(level=0)
      result_false = grouped.filter(
          lambda x: x.mean() > 1, dropna=False
      )
      expected_false = Series(
          [np.nan] * 9, index=np.repeat([1, 2, 3], 3)
      )
      tm.assert_series_equal(result_false, expected_false)
  
      result_true = grouped.filter(lambda x: x.mean() > 1, dropna=True)
      expected_true = Series(
          index=pd.Index([], dtype=int), dtype=np.float64
      )
      tm.assert_series_equal(result_true, expected_true)
  
imports: from string import ascii_lowercase
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Series, Timestamp
  import pandas._testing
label_desc: Use image node_id 27 for calling a global function with example usage: test_filter_dropna_with_empty_groups() without return types