code: def test_datetime_validate_value_none():
      dt = dt_2002
      dt_min = dt_1442
      dt_max = dt_2056
      w = DatetimePicker(value=dt, min=dt_min, max=dt_max)
      w.value = None
      assert w.value is None
  
file_path: catboost/contrib/python/ipywidgets/py3/ipywidgets/widgets/tests/test_widget_datetime.py
imports: import pytest
  from contextlib import nullcontext
  import datetime
  import itertools
  import pytz
  from traitlets import TraitError
  from ..widget_datetime import DatetimePicker
label_desc: Use image node_id 3 for calling a global function with example usage: test_datetime_validate_value_none() without return types