code: def test_nan_behaviour_ignore(df_enc_big_na):
      encoder = StringSimilarityEncoder(missing_values="ignore")
      X = encoder.fit_transform(df_enc_big_na)
      assert (X.isna().any(1) == df_enc_big_na.isna().any(1)).all()
      assert encoder.encoder_dict_ == {
          "var_A": ["B", "D", "G", "A", "C", "E", "F"],
          "var_B": ["A", "D", "B", "G", "C", "E", "F"],
          "var_C": ["C", "D", "B", "G", "A", "E", "F"],
      }
  
imports: from difflib import SequenceMatcher
  import pandas
  import pytest
  from feature_engine.encoding import StringSimilarityEncoder
  from feature_engine.encoding.similarity_encoder import _gpm_fast
label_desc: Use image node_id 8 for calling a global function with example usage: test_nan_behaviour_ignore(df_enc_big_na) without return types