# 定义函数def findMinAndMax(L):    if L ==[]:        return (None,None)    else:        min = L[0]        max = L[0]        for i in L:            if i <= min:                min = i        for j in L:            if j >= max:                max = j        return (min, max)#测试函数：if findMinAndMax([])!=(None,None):    print("测试不通过")elif findMinAndMax([1])!=(1,1):    print("测试不通过")elif findMinAndMax([3,1])!=(1,3):    print("测试不通过")elif findMinAndMax([10,76,7,34,8,90])!=(7,90):    print("测试不通过")else:    print("测试通过")

可以正常运行成功