class Student(object):

    count = 0

    def __init__(self, name):

        self.name = name

        Student.count = Student.count + 1

if Student.count != 0:

    print('测试失败!')

else:

    bart = Student('Bart')

    if Student.count != 1:

        print('测试失败!')

    else:

        lisa = Student('Bart')

        if Student.count != 2:

            print('测试失败!')

        else:

            print('Students:', Student.count)

            print('测试通过!')