code: def test_datetime_types() -> None:
      assert len(bus.DATETIME_TYPES) == 7
  
imports: from __future__ import annotations
  import pytest
  import datetime
  from math import inf, nan
  import numpy
  import pandas
  import pytz
  from tests.support.util.env import envset
  import bokeh.util.serialization
label_desc: Use image node_id 5 for calling a global function with example usage: test_datetime_types() without return types