code: def test_environment_variables(self):
      os.environ["KAGGLE_USERNAME"] = "dinosaur"
      os.environ["KAGGLE_KEY"] = "xxxxxxxxxxxx"
      api = KaggleApi()
  
      # We haven't authenticated yet
      self.assertTrue("key" not in api.config_values)
      self.assertTrue("username" not in api.config_values)
      api.authenticate()
  
      # Should be set from the environment
      self.assertEqual(api.config_values["key"], "xxxxxxxxxxxx")
      self.assertEqual(api.config_values["username"], "dinosaur")
  
file_path: kaggle-api/kaggle/tests/test_authenticate.py
imports: from kaggle.api.kaggle_api_extended import KaggleApi
  import os
  import unittest
label_desc: Use image node_id 3 for calling the TestAuthenticate obj's underlying member method code with example usage: obj.test_environment_variables() without return types