def get_system_flags ( ) -> FrozenSet [ Flag ] : return frozenset ( { Seen , Recent , Deleted , Flagged , Answered , Draft } )
python return a set
Return the set of implemented system flags .
def get_system_flags() -> FrozenSet[Flag]:
    """Return the set of implemented system flags."""
    return frozenset({Seen, Recent, Deleted, Flagged, Answered, Draft})