code: def test_non_fitted_error(df_vartypes):
      transformer = MockTransformer()
      with pytest.raises(NotFittedError):
          transformer.get_feature_names_out(df_vartypes)
  
imports: import numpy
  import pytest
  from sklearn.exceptions import NotFittedError
  from sklearn.impute import SimpleImputer
  from sklearn.pipeline import Pipeline
  from sklearn.preprocessing import PolynomialFeatures
  from feature_engine._base_transformers.mixins import GetFeatureNamesOutMixin
  from feature_engine.dataframe_checks import check_X
label_desc: Use image node_id 1 for calling a global function with example usage: test_non_fitted_error(df_vartypes) without return types