code: def modified(filename):
      '''
      Retrieve how long ago a file has been modified.
  
      :param filename: name of the file
  
      >>> print modified('/')             # doctest: +SKIP
      3 days ago
      '''
      if isinstance(filename, file):
          filename = filename.name
  
      return duration(os.stat(filename)[stat.ST_MTIME]f modified(filename):
      '''
      Retrieve how long ago a file has been modified.
  
      :param filename: name of the file
  
      >>> print modified('/')             # doctest: +SKIP
      3 days ago
      '''
      if isinstance(filename, file):
          filename = filename.name
  
      return duration(os.stat(filename)[stat.ST_MTIME])
docs: Retrieve how long ago a file has been modified.
  
      :param filename: name of the file
  
      >>> print modified('/')             # doctest: +SKIP
      3 days ago