class Student(object):    def __init__(self, name, gender):        self._name = name        self._gender = gender    def set_gender(self, gender):        self._gender = gender    def get_gender(self):        return self._genderbart = 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!')