def findMinAndMax(l):
    if l==[]:
        return None,None    else:
    a=l[0]#save the maximum number  
    b=l[0]#save the minimum number       
    for i in l:
            if a<i:
                a=i
            if b>i:
                b=i
    return b,a
if findMinAndMax([]) != (None, None):#粘贴代码时注意缩进问题  
    print('测试失败!')
elif findMinAndMax([7]) != (7, 7):
    print('测试失败!')
elif findMinAndMax([7, 1]) != (1, 7):
    print('测试失败!')
elif findMinAndMax([7, 1, 3, 9, 5]) != (1, 9):
    print('测试失败!')
else:
    print('测试成功!')