code: def setUp(self):
      self.to_json = date_serialization["to_json"]
      self.dummy_manager = None
  
imports: import array
  import datetime
  import pytest
  from unittest import TestCase
  from traitlets import HasTraits, Int, TraitError
  from traitlets.tests.test_traitlets import TraitTestBase
  from ipywidgets import Color, NumberFormat
  from ipywidgets.widgets.widget import _remove_buffers, _put_buffers
  from ipywidgets.widgets.trait_types import date_serialization, TypedTuple
label_desc: Use image node_id 1 for calling the TestDateSerialization obj's underlying member method code with example usage: obj.setUp() without return types