'Return the result from querying role assignment API + queried URL.
Calls GET /v3/role_assignments?<params> and returns its result, where
<params> is the HTTP query parameters form of effective option plus
filters, if provided. Queried URL is returned as well.
:returns: a tuple containing the list role assignments API response and
queried URL.'

def get_role_assignments(self, expected_status=http_client.OK, **filters):

    query_url = self._get_role_assignments_query_url(**filters)
    response = self.get(query_url, expected_status=expected_status)
    return (response, query_url)
