code: def test_sign_in(self):
      un = "anyone"
      ak = "something"
      # TODO, add this!
      # si = ['this', 'and-this']
      py.sign_in(un, ak)
      creds = py.get_credentials()
      self.assertEqual(creds["username"], un)
      self.assertEqual(creds["api_key"], ak)
  
file_path: plotly.py/packages/python/chart-studio/chart_studio/tests/test_plot_ly/test_plotly/test_credentials.py
imports: from __future__ import absolute_import
  import _plotly_utils.exceptions
  from chart_studio import plotly, exceptions
  import chart_studio.session
  import chart_studio.tools
  from chart_studio.tests.utils import PlotlyTestCase
  import sys
label_desc: Use image node_id 3 for calling the TestSignIn obj's underlying member method code with example usage: obj.test_sign_in() without return types