code: def test_datetimes():
      assert validate("time", time(12, 0, 0))
      assert validate("date", date(1999, 1, 20))
      assert validate("datetime", datetime(1999, 1, 20, 12, 0, 0))
  
file_path: datashader/datashader/datashape/tests/test_user.py
imports: import pytest
  from datashader.datashape.user import issubschema, validate
  from datashader.datashape import dshape
  from datetime import date, time, datetime
  import numpy
label_desc: Use image node_id 6 for calling a global function with example usage: test_datetimes() without return types