code: def test_unknown(self):
      c = complex(1, 2)
      result = serialize_json_safe([c, 42])
      assert result == [c, 42]
  
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 3 for calling the TestSerializationUtilities obj's underlying member method code with example usage: obj.test_unknown() without return types