有朋友会吗，帮一帮😭
如图，有朋友会做吗，我大一刚学，看不明白了，怎么码都在报错，求帮
def func(n, s):
if n == 1:
return '{' + s + '}'
else:
s += ','+s[0]+s+s[-1]+','
return func(n - 1, s[:-1])
print(func(3, '{}'))
def func(n, s):
if n == 1:
return '{' + s + '}'
else:
s += ','+s[0]+s+s[-1]+','
return func(n - 1, s[:-1])
print(func(3, '{}'))