code: def test_fit_raises_error_if_na_in_inut_df(df_na):
      # test case 8: when dataset contains na, fit method
      with pytest.raises(ValueError):
          transformer = Winsorizer()
          transformer.fit(df_na)
  
imports: import math
  import numpy
  import pandas
  import pytest
  from feature_engine.outliers import Winsorizer
label_desc: Use image node_id 21 for calling a global function with example usage: test_fit_raises_error_if_na_in_inut_df(df_na) without return types