old_contents: import pytest
  
  
  @pytest.fixture(scope='session')
  def session_capabilities(session_capabilities):
      session_capabilities.setdefault('tags', []).append('treeherder')
      return session_capabilities
  
  
  @pytest.fixture
  def selenium(selenium):
      selenium.maximize_window()
      return selenium
  
new_contents: import pytest
  
  
  @pytest.fixture
  def capabilities(request, capabilities):
      driver = request.config.getoption('driver')
      if capabilities.get('browserName', driver).lower() == 'firefox':
          capabilities['marionette'] = True
      return capabilities
  
  
  @pytest.fixture(scope='session')
  def session_capabilities(pytestconfig, session_capabilities):
      if pytestconfig.getoption('driver') == 'SauceLabs':
          session_capabilities.setdefault('tags', []).append('treeherder')
      return session_capabilities
  
  
  @pytest.fixture
  def selenium(selenium):
      selenium.maximize_window()
      return selenium
  
subject: Switch to using Marionette/geckodriver (#2656)