def binary_search(list,item):
low=0
high=len(list)-1
while low<=high:
mid=(low+high)/2
guess=list[mid]
if guess==item:
return mid
if guess<item:
return low=mid+1
else:
return high=mid-1
return None
my_list=[1,3,5,7,9]
binary_search(my_list,-1)
File "<ipython-input-6-b0d18351752a>", line 10 return low=mid+1 ^ SyntaxError: invalid syntax 显示语法错误到底哪里错误啊