马和骆驼都是哺乳动物，它们都有四只脚，体型也差不多大，我们将在这里为它们编写属于它们各自的类，输出相关语句。

例如：一匹阿拉伯12岁的公马，在草原上奔跑的速度为50km/h。

一匹双峰驼20岁的母骆驼，在沙漠上奔跑的速度为40kmh。

class Horse():
    def __init__(self, category, gender, age):
        self.category = category
        self.gender = gender
        self.age = age
        self.speed = 0
    def get_descriptive(self):
        self.info = "一匹" + self.category + str(self.age) + "岁的" + self.gender + "马"
    def write_speed(self, new_speed):
        self.speed= new_speed
        addr = "在草原上奔跑的速度为"
        print(self.info + "，" + addr + str(self.speed) + "km/h。")
class Came1(        ①        ):
    def __init__(self, category, gender, age):
        super().__init__(category, gender, age)
    def write_speed(self,new_speed):
                   ②        
        addr = "在沙漠上奔跑的速度为"
        print(        ③        ("马","骆驼") + "，" + addr +        ④        + "km/h。")

horse = Horse("阿拉伯","公",12)
horse.get_descriptive()
horse.write_speed(50)
came1 = Came1("双峰驼","母",20)
came1.get_descriptive()
came1. write_speed(40)