code: def test_different_null_types():
      # Arrange
      data = {"col1": [np.NAN, np.NaN, pd.NA, "value", "NULL"]}
      dataframe = pd.DataFrame(data=data)
      # Act
      result = MixedNulls().run(dataframe)
      # Assert
      assert_that(
          result.value["columns"], has_entry("col1", has_length(3))
      )
  
imports: import numpy
  import pandas
  from hamcrest import any_of, assert_that, calling, close_to, equal_to, greater_than, has_entries, has_entry, has_items, has_length, is_, raises
  from deepchecks.core.errors import DatasetValidationError, DeepchecksValueError
  from deepchecks.tabular.checks.data_integrity.mixed_nulls import MixedNulls
  from deepchecks.tabular.dataset import Dataset
  from tests.base.utils import equal_condition_result
label_desc: Use image node_id 5 for calling a global function with example usage: test_different_null_types() without return types