class Student(object):

    def __init__(self, name, gender):

        self.name = name

        self.__gender = gender

    def get_name(self):

        return self.name

    def get_gender(self):

        return self.__gender

    def set_gender(self, gender):

        self.__gender = gender

bart = Student('Bart', 'male')

if bart.get_gender() != 'male':

    print('测试失败!')

else:

    bart.set_gender('female')

    if bart.get_gender() != 'female':

        print('测试失败!')

    else:

        print('测试成功!')