类的定义格式：

class Name(Father_class):def __init__(self, para, ...):self.para = xdef __init__(self, para, ...):super().__init__(para, ...)	#调用父类的构造函数

class Car():def __init__(self,make,model,year):	#构造函数self.make = makeself.model = modelself.year = yearself.odometer_reading = 0def get_descriptive_name(self):long_name = str(self.year) + ' ' + self.make + ' ' + self.modelreturn long_name.title()def read_odometer(self):print('This car has ' + str(self.odometer_reading) + ' miles on it.')def update_odometer(self,mileage):if mileage >= self.odometer_reading:self.odometer_reading = mileageelse:print('You can not roll back an odometer！')def increment_odometer(self, miles):if miles < 0:print('You can cheat me！ driving miles < 0')else:print('driving this car ' + str(miles) + 'miles')self.odometer_reading += milesdef fill_gas_tank(self):print('This car need fill gas !')class Battery():def __init__(self, battery_size=70):	#构造函数，带默认参数值self.battery_size = battery_sizedef describe_battery(self):print('This car has a ' + str(self.battery_size) + '-KWh battery.')def upgrade_battery(self):if self.battery_size != 85:self.battery_size = 85print("battery update successfully !")def get_range(self):if self.battery_size == 70:range = 240elif self.battery_size == 85:range = 270message = 'This car can go approximately ' + str(range)message += ' miles on a full charge.'print(message)class ElectricCar(Car):		#类的继承def __init__(self, make, model, year):super().__init__(make, model, year)	#调用父类初始化函数初始化父类成员self.battery = Battery()			#新的成员，一个Battery对象def fill_gas_tank(self):# super().fill_gas_tank()print('This car doesn\'t need a gas tank!')my_tesla = ElectricCar('tesla','model s', 2019)
print(my_tesla.get_descriptive_name())
my_tesla.battery.describe_battery()
my_tesla.fill_gas_tank()
my_tesla.battery.get_range()
my_tesla.battery.upgrade_battery()
my_tesla.battery.get_range()