def findMinAndMax(L):    from collections.abc import Iterable    while isinstance(L,Iterable):        if L== []:            return None, None        L_max = L[0]        L_min = L[0]        for i in range(len(L)):            if L[i] > L_max:                    L_max = L[i]        for i in range(len(L)):            if L[i] < L_min:                    L_min = L[i]        return L_min, L_max    return None, Noneif 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!')elif findMinAndMax(123) !=(None,None):    print('测试失败')else:    print('测试成功!')