如何求列表内含有列表里所有数字的和

ll=[21,2,[3,54],[23,3,5],5,[2,5,76,23],56,[6,5,43,56],3,[56,76],89,7]
计算所有数字的和

如果只有一层嵌套可以这么写

total=0
for ele in ll:
    if (isinstance(ele,list)):
        total += sum(ele)
    else:
        total += ele

 
def cal(ele):
    total = 0
    if (isinstance(ele,list)):
        for e in ele:
            total += cal(e)
    else:
        total += ele
    return total

ll = [21,2,[3,54],[23,3,5],5,[2,5,76,23],56,[6,5,43,56],3,[56,76],89,7]
print(cal(ll))