':return: A set which contains the session ID parameters (if any)'

def _has_sessid(self, uri):

    sessid_in_uri = set()
    if uri.has_query_string():
        query_string = uri.get_querystring()
        params = set(query_string.keys())
        sessid_in_uri = self.SESSID_PARAMS.intersection(params)
    return sessid_in_uri
