class Student:
    school = '中北'
    def __init__(self, name):
        self.name=name
    @classmethod
    def printschool(cls, a):
        print(cls.school)
        print(a)
    @staticmethod
    def add(a, b, c):
        print('{0}+{1}+{2}={3}'.format(a, b, c, (a+b+c)))
Student.printschool(4)
Student.add(1,2,3)
s1 = Student('jzh')
s2 = Student
print(s2.school)
s2.add(1,2,3)
print(s1.school)
print(Student.school)
s1.add(1,2,3)   #?1
s1.printschool(4)   #?2
s2.printschool(4)实例对象可以调用静态方法(?1处)和类方法(?2处)吗?