old_contents: import os
  
  BASE_PATH = os.path.abspath(os.path.dirname(__file__))
  
  PRO_CONF_PATH = '/etc/skylines/production.py'
  DEV_CONF_PATH = os.path.join(BASE_PATH, 'default.py')
  TESTING_CONF_PATH = os.path.join(BASE_PATH, 'testing.py')
  
  
  def to_envvar(path=None):
      """
      Loads the application configuration from a file.
      Returns the configuration or None if no configuration could be found.
      """
  
      if path:
          path = os.path.abspath(path)
          if not os.path.exists(path):
              return
      elif os.path.exists(PRO_CONF_PATH):
          path = PRO_CONF_PATH
      elif os.path.exists(DEV_CONF_PATH):
          path = DEV_CONF_PATH
      else:
          return
  
      os.environ['SKYLINES_CONFIG'] = path
      return True
  
  
  def use_testing():
      os.environ['SKYLINES_CONFIG'] = TESTING_CONF_PATH
  
new_contents: import os
  
  BASE_PATH = os.path.abspath(os.path.dirname(__file__))
  
  PRO_CONF_PATH = '/etc/skylines/production.py'
  DEV_CONF_PATH = os.path.join(BASE_PATH, 'default.py')
  TESTING_CONF_PATH = os.path.join(BASE_PATH, 'testing.py')
  
  
  def to_envvar(path=None):
      """
      Loads the application configuration from a file.
      Returns the configuration or None if no configuration could be found.
      """
  
      if path:
          path = os.path.abspath(path)
          if not os.path.exists(path):
              return
      elif os.path.exists(PRO_CONF_PATH):
          path = PRO_CONF_PATH
      elif os.path.exists(DEV_CONF_PATH):
          path = DEV_CONF_PATH
      else:
          return
  
      os.environ['SKYLINES_CONFIG'] = path
      return True
  
  
  def use_testing():
      os.environ['SKYLINES_CONFIG'] = TESTING_CONF_PATH
  
  # Make sure use_testing() is not detected as a unit test by nose
  use_testing.__test__ = False
  
subject: Make sure use_testing() is not detected as a unit test by nose