自编python课程小游戏，问题求助！！！

落梦

from random import choice
score_you = 0
score_com = 0
print('plaese select your direction !')
print('left front right')
def fof():
    you = input()
    print ('you select' + you)
    l = ['left' 'front' 'right']
    com = choice (l)
    print('computer saved'+ com)
    if you!=com:
        score_you = score_you + 1
        print ('good')
    else:
        score_com = score_com + 1
        print ('bad')
fof()
fof()
fof()
fof()
if score_com < score_you:
    print('congrdulation! you win')
else:
    print('disapproint! you faild')python基础27课小游戏自编代码，错误如下：


"C:\Program Files\Python38\python.exe" C:/Users/23593/Desktop/.idea/list切片.py
plaese select your direction !
left front right
left
Traceback (most recent call last):
  File "C:/Users/23593/Desktop/.idea/list切片.py", line 18, in <module>
you selectleft
computer savedleftfrontright
    fof()
  File "C:/Users/23593/Desktop/.idea/list切片.py", line 13, in fof
    score_you = score_you + 1
UnboundLocalError: local variable 'score_you' referenced before assignment

求解！！！！！