class Student(object):    count = 0    def __init__(self, name):        self.name = name        Student.count=Student.count+1# 测试: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!')