请使用迭代查找一个list中最小和最大值，并返回一个tuple：# 测试 if findMinAndMax([]) != (None, None): print('测试失败!') elif findMinAndMax([7]) != (7, 7): print('测试失败!') elif findMinAndMax([7, 1]) != (1, 7): print('测试失

def findminmax(L):
    a = []
    if L != a:
        min = L[0]
        max = L[0]
        for i in L:
            if min > i:
                min = i
            if max < i:
                max = i
            i = i + 1
        return(min, max)
    else:
        return(None, None)

def findminmax(L):
    if len(L) > 0:
        return(min(L), max(L))
    else:
        return(None, None)