code: def test_handle_unknown_error(self):
      # BaseN has problems with None -> ignore None
      X = th.create_dataset(n_rows=100, has_missing=False)
      X_t = th.create_dataset(n_rows=50, extras=True, has_missing=False)
  
      for encoder_name in set(encoders.__all__) - {
          "HashingEncoder"
      }:  # HashingEncoder supports new values by design -> excluded
          with self.subTest(encoder_name=encoder_name):
              # new value during scoring
              enc = getattr(encoders, encoder_name)(
                  handle_unknown="error"
              )
              enc.fit(X, y)
              with self.assertRaises(ValueError):
                  _ = enc.transform(X_t)
  
imports: import warnings
  from datetime import timedelta
  import numpy
  from numpy.testing import assert_array_equal
  import pandas
  import sklearn
  import tests.helpers
  from sklearn.utils.estimator_checks import check_transformer_general, check_transformers_unfitted, check_n_features_in
  from sklearn.compose import ColumnTransformer
  from unittest import TestCase
  from copy import deepcopy
  import category_encoders
label_desc: Use image node_id 6 for calling the TestEncoders obj's underlying member method code with example usage: obj.test_handle_unknown_error() without return types