code: def test_no_mix_nan():
      # Arrange
      data = {
          "col1": [np.nan, "bar", "cat"],
          "col2": ["a", np.nan, np.nan],
      }
      dataframe = pd.DataFrame(data=data)
      # Act
      result = MixedDataTypes().run(dataframe)
      # Assert
      assert_that(result.value, equal_to({"col1": {}, "col2": {}}))
  
imports: import numpy
  import pandas
  from hamcrest import assert_that, calling, close_to, equal_to, greater_than, has_entries, has_entry, has_items, has_length, raises
  from deepchecks.core import ConditionCategory
  from deepchecks.core.errors import DeepchecksValueError
  from deepchecks.tabular.checks.data_integrity.mixed_data_types import MixedDataTypes
  from deepchecks.tabular.dataset import Dataset
  from tests.base.utils import equal_condition_result
label_desc: Use image node_id 14 for calling a global function with example usage: test_no_mix_nan() without return types