声明一个车(vehicle)基类，具有MaxSpeed,Weight等成员变量(私有，使用属性进行读写)，Run，Stop等成员函数，由此派生出自行车(bicycle)类，汽车(motorcar)类。自行车(bicycle)类有高度(Height)等属性，汽车(motorcar)类有座位数(SeatNum)等属性。从bicycle和motorcar派生出摩托车(motocycle)类。编写程序验证继承关系。

好的，您的问题是如何声明一个车(vehicle)基类，派生出自行车(bicycle)类和汽车(motorcar)类，并从它们派生出摩托车(motorcycle)类，并验证继承关系。

以下是需要编写的代码：

class Vehicle:
    def __init__(self, max_speed, weight):
        self._max_speed = max_speed
        self._weight = weight

    @property
    def max_speed(self):
        return self._max_speed

    @max_speed.setter
    def max_speed(self, value):
        self._max_speed = value

    @property
    def weight(self):
        return self._weight

    @weight.setter
    def weight(self, value):
        self._weight = value

    def run(self):
        print('Vehicle is running.')

    def stop(self):
        print('Vehicle has stopped.')


class Bicycle(Vehicle):
    def __init__(self, max_speed, weight, height):
        super().__init__(max_speed, weight)
        self._height = height

    @property
    def height(self):
        return self._height

    @height.setter
    def height(self, value):
        self._height = value


class Motorcar(Vehicle):
    def __init__(self, max_speed, weight, seat_num):
        super().__init__(max_speed, weight)
        self._seat_num = seat_num

    @property
    def seat_num(self):
        return self._seat_num

    @seat_num.setter
    def seat_num(self, value):
        self._seat_num = value


class Motorcycle(Bicycle, Motorcar):
    def __init__(self, max_speed, weight, height, seat_num):
        Bicycle.__init__(self, max_speed, weight, height)
        Motorcar.__init__(self, max_speed, weight, seat_num)


# 验证继承关系
bike = Bicycle(20, 10, 30)
bike.run()
bike.stop()
print(bike.max_speed)
print(bike.weight)
print(bike.height)

car = Motorcar(80, 1000, 5)
car.run()
car.stop()
print(car.max_speed)
print(car.weight)
print(car.seat_num)

moto = Motorcycle(100, 500, 25, 2)
moto.run()
moto.stop()
print(moto.max_speed)
print(moto.weight)
print(moto.height)
print(moto.seat_num)

这段代码声明了一个`Vehicle`基类，其中包含了`MaxSpeed`和`Weight`等成员变量，也有`Run`和`Stop`等成员函数。从`Vehicle`类派生出`Bicycle`和`Motorcar`类，并分别在子类中添加了`Height`和`SeatNum`等属性。最后，从`Bicycle`和`Motorcar`类中派生出`Motorcycle`类。

我们验证了继承关系，通过创建`Bicycle`、`Motorcar`和`Motorcycle`对象，并使用基类和派生类的成员函数、属性来操作它们的对象。