class Ship:
def __init__(self, pos, vel, angle, image, info):
self.pos = [pos[0],pos[1]]
self.vel = [vel[0],vel[1]]
def keydown(key):
global current_key
current_key=simplegui.KEY_MAP['down']
pos_increment=15
posx=Ship.shipx
posy=Ship.shipy
print current_key
print posx,posy
错误是 AttributeError:'Ship' 对象没有属性 'shipx'。请帮助