class Toy: head = 10 body = 20 def __init__(self, x=1, y=2): self.head1 = x self.body1 = y def run(self): # self points at obj; self is dummy variable;self is simple variable print("toy runs", self.head,self.head1) def run2(self, x, y): print("toy runs", x, y) def obj_name(self): print(self.__str__()) def obj_name2(self): self.__str__ = self.head print(self.__str__) toy1 = Toy() toy2 = Toy(0,0) toy3 = Toy(1,2) toy4 = Toy(3,4) print(toy1, toy2) print(toy1.head,toy2.body,toy1.run()) # Result = 10,20,None toy1.run() print(Toy.__dict__) print(toy3.head1, toy3.body1, toy4.head1, toy4.body1) toy3.run2(12,13) def b(): print("Hello") toy1.say_hello = b print(toy1.say_hello.__defaults__) print(toy1.say_hello.__class__) print(toy1.say_hello.__name__) toy1.say_hello() toy1.obj_name() toy1.obj_name2() print(dir(toy1)) # Original del toy1.say_hello del toy1.head1 print(dir(toy1)) # latest import inspect print(inspect.getmembers(toy1)) # inspect.getmembers() <- get more details of class; we can see the content of class object