code: def setUp(self):
      pio.templates.default = None
  
imports: import json
  import os
  from unittest import TestCase
  import pytest
  import plotly
  import plotly.io
  from plotly.io._utils import plotly_cdn_url
label_desc: Use image node_id 1 for calling the PlotlyOfflineTestCase obj's underlying member method code with example usage: obj.setUp() without return types