def get_subscriber_emails(stream: Stream, requesting_user: Optional[UserProfile]=None) -> List[str]:
    subscriptions_query = get_subscribers_query(stream, requesting_user)
    subscriptions = subscriptions_query.values('user_profile__email')
    return [subscription['user_profile__email'] for subscription in subscriptions]
def get_subscriber_emails(stream: Stream, requesting_user: Optional[UserProfile]=None) -> List[str]:
    subscriptions_query = get_subscribers_query(stream, requesting_user)
    subscriptions = subscriptions_query.values('user_profile__email')
    return [subscription['user_profile__email'] for subscription in subscriptions]