为什么对应的sum=0 sum=n+sum无结果

``` def r(k):
n=1
if k==1:
name=input('hello,your name:')
sum=0
sum=sum+n
return
if k>1:
names=['kkkk','kssd']
for name in names:
print(names)
return

r(4)
['kkkk', 'kssd']
r(1)
hello,your name:rot

sum=sum+n
return
->
sum=sum+n
return name