Fields.URL Holds an URL and give access to its components class Fields.URL: self.url def __init__ (self, url): URL store in a homegeneous manner file names and general URL objects, so that they can be accessed by the same methods. A URL object is hashable and can be used as a dictionnary key. Holds the tuple describing the URL. Instantiates an URL from its string description. In the case of a file, user directory expansion is performed.