'``relative`` is whether the path should be relative to the location
of the config file (absolute paths will still be absolute). If
``directory`` is True, the path must indicate a directory, rather than
a file.'

def __init__(self, name, relative=True, directory=False, default=None):

    super(FilenameAttribute, self).__init__(name, default=default)
    self.relative = relative
    self.directory = directory
