code: def test_value_frequency():
      assert_that(
          value_frequency(np.array([1, 1, 1, 2, 2, 1, 3, 3, 3, 0])),
          equal_to([0.4, 0.2, 0.3, 0.1]),
      )
      assert_that(
          value_frequency([1, np.NAN, 1, 1, 3, np.NAN, 3, 0]),
          equal_to([0.375, 0.25, 0.25, 0.125]),
      )
  
file_path: deepchecks/tests/utils/preprocessing_test.py
imports: import numpy
  from hamcrest import assert_that, calling, equal_to, raises
  from deepchecks.core.errors import DeepchecksValueError
  from deepchecks.utils.distribution.preprocessing import OTHER_CATEGORY_NAME, preprocess_2_cat_cols_to_same_bins, value_frequency
label_desc: Use image node_id 5 for calling a global function with example usage: test_value_frequency() without return types