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 __init__(self, x, y, w, h):
		self.x = x
		self.y = y
		self.w = w
		self.h = h
		self.center = (self.x+int(self.w/2),self.y+int(self.h/2))
		self.distance_from_center = sqrt((self.center[0]-MAP_WIDTH/2)**2 + (self.center[1]-MAP_HEIGHT/2)**2)