def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def init(num_players):
	global MAP_WIDTH,MAP_HEIGHT,N_ITERATIONS,H_RATIO,W_RATIO,MIN_ROOM_SIDE,CENTER_HUB_HOLE,CENTER_HUB_RADIO,MAP_NAME
	MAP_WIDTH=int(500*sqrt(num_players))
	MAP_HEIGHT=MAP_WIDTH
	N_ITERATIONS=log(MAP_WIDTH*100,2)
	H_RATIO=0.49
	W_RATIO=H_RATIO
	MIN_ROOM_SIDE = 32
	CENTER_HUB_HOLE = 32
	CENTER_HUB_RADIO = CENTER_HUB_HOLE-MIN_ROOM_SIDE/2
	MAP_NAME="result%s.png"%MAP_WIDTH