# -*- coding: utf-8 -*-

def findMinAndMax(L):

 if len(L)==0:

      return(None,None)

 else:

    max=L[0]

    min=L[0]    

    for num in L:

        if num>max:

          max=num

        if num<min:

          min=num

    return (min, max)

# 测试

if findMinAndMax([]) != (None, None):

    print('测试空值失败!')

elif findMinAndMax([7]) != (7, 7):

    print('测试7失败!')

elif findMinAndMax([7, 1]) != (1, 7):

    print('测试7,1失败!')

elif findMinAndMax([7, 1, 3, 9, 5]) != (1, 9):

    print('测试7,1,3,9,5失败!')

else:

    print('测试成功!')