code: def file(cls, path, encoding=None, parser=None):
          
          cls.__hierarchy.append(file.File(path, encoding, parser))
docs: Set a file as a source.
  
          File are parsed as literal python dicts by default, this behaviour
          can be configured.
  
          Args:
              path: The path to the file to be parsed
              encoding: The encoding of the file.
                  Defaults to 'raw'. Available built-in values: 'ini', 'json', 'yaml'.
                  Custom value can be used in conjunction with parser.
              parser: A parser function for a custom encoder.
                  It is expected to return a dict containing the parsed values
                  when called with the contents of the file as an argument.