code: def test_categorical_methods_mixin_transform_ignore_unseen():
      input_df = pd.DataFrame({"words": ["dog", "dig", "bird"]})
      output_df = pd.DataFrame({"words": [1, 0.66, np.nan]})
      enc = MockClass(unseen="ignore")
      pd.testing.assert_frame_equal(enc.transform(input_df), output_df)
  
file_path: feature_engine/tests/test_encoding/test_base_encoder.py
imports: import numpy
  import pandas
  import pytest
  from feature_engine.encoding.base_encoder import CategoricalInitMixin, CategoricalMethodsMixin
label_desc: Use image node_id 3 for calling a global function with example usage: test_categorical_methods_mixin_transform_ignore_unseen() without return types