'Args:
hs (HomeServer)
room_id (str)
rules_for_room_cache(Cache): The cache object that caches these
RoomsForUser objects.'

def __init__(self, hs, room_id, rules_for_room_cache):

    self.room_id = room_id
    self.is_mine_id = hs.is_mine_id
    self.store = hs.get_datastore()
    self.linearizer = Linearizer(name='rules_for_room')
    self.member_map = {}
    self.rules_by_user = {}
    self.state_group = object()
    self.sequence = 0
    self.uninteresting_user_set = set()
    self.invalidate_all_cb = _Invalidation(rules_for_room_cache, room_id)
