code: def _assert_check_unknown(
      values, uniques, expected_diff, expected_mask
  ):
      diff = _check_unknown(values, uniques)
      assert_array_equal(diff, expected_diff)
  
      diff, valid_mask = _check_unknown(
          values, uniques, return_mask=True
      )
      assert_array_equal(diff, expected_diff)
      assert_array_equal(valid_mask, expected_mask)
  
file_path: scikit-learn/sklearn/utils/tests/test_encode.py
imports: import pickle
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from sklearn.utils._encode import _check_unknown, _encode, _get_counts, _unique
label_desc: Use image node_id 3 for calling a global function with example usage: _assert_check_unknown(values, uniques, expected_diff, expected_mask) without return types