如何用python使用递归实现1加到100

# result = 1+2+3+.....99+100
def sum_num(num):
    # num =2
    if num == 1:
        return 1
    # 返回值 自己调用自己
    return num + sum_num(num - 1)


print(sum_num(100))
'''
函数调用
num=1,  sum_num(1) = 1 
num=2,  sum_num(2) = num+sum_num(num-1)=2+sum_num(1)=2+1=3
num=3,  sum_num(3) = num+sum_num(num-1)=3+sum_num(2)=3+3=6
num = 4, sum_num(4)= num + sum_num(num-1) = 4 + sum_num(3) = 4 t 6 = 10

.....

num = 100，sum_num(100) = num + sum_num(num-1) = 100 + sum_num(99) = 100 + 4950 = 5050

'''