code: def test_nan_to_null(self):
      array = [1, float("NaN"), float("Inf"), float("-Inf"), "platypus"]
      result = _json.dumps(array, cls=utils.PlotlyJSONEncoder)
      expected_result = '[1, null, null, null, "platypus"]'
      self.assertEqual(result, expected_result)
  
imports: import datetime
  import math
  import decimal
  from datetime import datetime
  from unittest import TestCase
  from time import time
  import pytest
  import numpy
  import pandas
  import pytz
  from pandas.testing import assert_series_equal
  import json
  import os
  import base64
  from plotly import optional_imports, utils
  import plotly.graph_objects
  from plotly.graph_objs import Scatter, Scatter3d, Figure, Data
  from plotly.utils import get_by_path
  from PIL import Image
label_desc: Use image node_id 21 for calling the TestJSONEncoder obj's underlying member method code with example usage: obj.test_nan_to_null() without return types