code: def __init__(self, *args, **kwargs):
      self._credentials = None
      self._config = None
      self._graph_reference = None
      self._session = None
      super(PlotlyTestCase, self).__init__(*args, **kwargs)
  
file_path: plotly.py/packages/python/chart-studio/chart_studio/tests/utils.py
imports: import copy
  from unittest import TestCase
  from chart_studio import session, files, utils
  from plotly.files import ensure_writable_plotly_dir
label_desc: Use image node_id 1 to create a new PlotlyTestCase object from inherited base classes: TestCase with example: obj = PlotlyTestCase()