Python regexp

def __init__(self):
        self.cookies = None
        self.url = None
        self._source_url = None
        self._url_reg = re.compile("^(?:(?:(https?:)?(//[^/?#]+)))?(/[^?#]+/|/)?([^?#]+)?([^#]*)(.*)$", re.IGNORECASE)
        self._url_groups = [""] * len(self._url_reg.match("").groups())