多态：
一种接口多种形态；
作用，实现接口的重用
class Animal(object):
def __init__(self, name): # Constructor of the class
self.name = name
def talk(self): # Abstract method, defined by convention only
raise NotImplementedError("Subclass must implement abstract method")
class Cat(Animal):
def talk(self):
print('%s: 喵喵喵!' %self.name)
class Dog(Animal):
def talk(self):
print('%s: 汪！汪！汪！' %self.name)
def func(obj): #一个接口，多种形态
obj.talk()
c1 = Cat('小晴')
d1 = Dog('李磊')
func(c1)
func(d1)
真实案例：
class Flight(object):
def __init__(self,name):
self.flight_name = name
def checking_status(self):
print("checking flight %s status " %self.flight_name)
return 2
@property
def flight_status(self):
status = self.checking_status()
if status == 0:
print("flight got canceled....")
elif status == 1:
print("flight is arrivied....")
elif status == 2:
print("flight has departure....")
else:
print("can't confirm the flight's status.....")
f = Flight("CA980")
f.flight_status