def get_next_id(self):
        try:
            query = {'_id': 'last_id'}
            update = {'$inc': {'id': 1}}
            fn = self.db.internal.find_and_modify
            row = fn(query, update, upsert=True, new=True)
        except Exception as e:
            raise DatabaseException(e)
        return row['id']
def _split_horizontal(container):
		r1 = None
		r2 = None
		min_h = int(H_RATIO*container.w)+1
		if container.h < 2*min_h:
			return None
		r1 = Container(container.x,container.y,container.w,randint(min_h, container.h-min_h))
		r2 = Container(container.x,container.y+r1.h,container.w,container.h-r1.h)
		return [r1, r2]