def sum_and_multi(array: list) -> int:
"""
sums even-indexes elements and multiply at the last
"""
sum = 0
if array == []:
return sum
even_index_list = array[0:len(array):2]
for i in even_index_list:
sum += i
return sum * array[-1]
这个题主要就注意好一点,一定要添加判断列表为空的情况,不设置这个条件返回的是none,而none不等于0(本身不是同个对象所以不相等,但是他们的bool值是相等的,即bool(none) == bool(0)