python中什么是类方法

class A(object): 

    def foo(self,x): 

    #类实例方法 

        print "executing foo(%s,%s)"%(self,x) 

    @classmethod 

    def class_foo(cls,x): 

    #类方法 

        print "executing class_foo(%s,%s)"%(cls,x) 

    @staticmethod 

    def static_foo(x): 

    #静态方法 

        print "executing static_foo(%s)"%x

a = A() 

a.foo(1)     //print   : executing foo(<__main__.A object at 0xb77d67ec>,1)

a.class_foo(1)    //executing class_foo(<class '__main__.A'>,1) 

A.class_foo(1)    //executing class_foo(<class '__main__.A'>,1)