求一个用Python编的贪吃蛇游戏

我有个在手机上运行的。
代码如下：
import appuifw
import math
import e32
from key_codes import *
from graphics import *
import random

class SnakeGame:
deltas=((1,0),(0,-1),(-1,0),(0,1))
def __init__(self):
self.direction=0
self.step=5
self.color=(0,128,0)
self.fillarray={}
self.exitflag=0
self.score=0
self.wormlocs=[]
self.wormlength=10
self.foodloc=None
self.fieldcolor=(192,192,128)
self.resboxoffset=2
self.state='init'
self.old_body=appuifw.app.body
self.canvas=appuifw.Canvas(redraw_callback=self.redraw)
self.draw=Draw(self.canvas)
appuifw.app.body=self.canvas
self.fieldsize=(self.canvas.size[0]/self.step,(self.canvas.size[1]-16)/self.step)
self.canvas.bind(EKeyRightArrow,l