code: def test_serialize_timestamp(self):
      datetime_str = "2020-10-10"
      datetime_object = datetime.datetime.strptime(
          datetime_str, "%Y-%m-%d"
      )
      result = serialize_json_safe(datetime_object)
      assert datetime_str in result
  
imports: import datetime
  import json
  import numpy
  import pandas
  import pytest
  from scipy.sparse import csr_matrix
  from raiutils.data_processing import convert_to_list, convert_to_string_list_dict, serialize_json_safe
label_desc: Use image node_id 8 for calling the TestSerializationUtilities obj's underlying member method code with example usage: obj.test_serialize_timestamp() without return types