def findMinAndMax(L):    if len(L) == 0:        return (None, None)    max = L[0]    min = L[0]    for i in L:        if i > max:            max = i        if i < min:            min = i    return (min, max)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('测试失败!')elif findMinAndMax([7, 1, 3, 9, 5]) != (1, 9):    print('测试失败!')else:    print('测试成功!')

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