'Returns the set of users who share a room with `user_id`
Args:
user_id(str): Must be a local user
Returns:
dict: user_id -> share_private mapping'

@cachedInlineCallbacks(max_entries=500000, iterable=True)
def get_users_who_share_room_from_dir(self, user_id):

    rows = (yield self._simple_select_list(table='users_who_share_rooms', keyvalues={'user_id': user_id}, retcols=('other_user_id', 'share_private'), desc='get_users_who_share_room_with_user'))
    defer.returnValue({row['other_user_id']: row['share_private'] for row in rows})
