递归函数

def sum(l):    #print(l)    if not l:  #l为空时，递归循环结束        return 0    else:        return l[0]+sum(l[1:]) #递归调用        print(sum([1,2,3,4,5]))def sum1(l):    first,*rest=l    return first if not rest else first+sum1(rest)print(sum1(('a','b','c')))