create a base class called Vehicle with name, max_speed, and tank_size attributes. Then create a derived class called Truck that inherits from the Vehicle class. The Truck should have an additional attribute called seating_capacity with a default value of 5. The child class should have a method named range to calculate fuel efficiency - the calculation should be: max_speed * seating_capacity * tank_size. Override the method such that it can accept 1, 2, or 3 positional arguments. 

 

1)In-Vehicle, give all parameters a default value of None

2)In Truck, please remove the __init__ method. By not including an __init__ method, it will by default use the parent's

3)Your range method should take in a single parameter (seating_capacity) which is set to a default of 5. Inside this method, assign self.seating capacity, then use if statements to check what class attributes have been assigned

4)If max_speed, tank_size, and seating_capacity are all not None, then you can multiply 

5)If max_speed and seating_capacity are not None, you can multiply those instead

6)If the only seating_capacity is not None (which it won't be because you have provided a default value of 5), that will be what you return

class Vehicle:

    def __init__(self, name=None, max_speed=None, tank_size=None):
        '''instance constructor'''
        self.name = name
        self.max_speed = max_speed
        self.tank_size = tank_size


class Truck(Vehicle):

     def range(self, seating_capacity=5):
        '''instance method'''
        # assign atribute
        self.seating_capacity = seating_capacity

        # initialize total to default to seating_capacity as it is always not None
        total = self.seating_capacity
        # check attributes if not None
        if self.max_speed is not None:
            total *= self.max_speed
        if self.tank_size is not None:
            total *= self.tank_size
        # return total to caller
        return total

Step-by-step explanation

Here is the complete source code, kindly see inline comments for explanation. You may also view and run it from here for testing: https://repl.it/@dobizz/SoreNecessaryArchitect

class Vehicle:

    def __init__(self, name=None, max_speed=None, tank_size=None):
        '''instance constructor'''
        self.name = name
        self.max_speed = max_speed
        self.tank_size = tank_size


class Truck(Vehicle):

     def range(self, seating_capacity=5):
        '''instance method'''
        # assign atribute
        self.seating_capacity = seating_capacity

        # initialize total to default to seating_capacity as it is always not None
        total = self.seating_capacity
        # check attributes if not None
        if self.max_speed is not None:
            total *= self.max_speed
        if self.tank_size is not None:
            total *= self.tank_size
        # return total to caller
        return total

def tests():
    v = Vehicle('Vehicle1', 100, 60)
    assert isinstance(v, Vehicle)
    assert type(v) == Vehicle

    truck1 = Truck()
    truck2 = Truck('Truck 2', 100)
    truck3 = Truck('Truck 3', 120, 60)
    # check type and inheritance
    assert isinstance(truck1, Vehicle)
    assert isinstance(truck1, Truck)
    assert type(truck1) == Truck
    assert isinstance(truck2, Vehicle)
    assert isinstance(truck2, Truck)
    assert type(truck2) == Truck
    assert isinstance(truck3, Vehicle)
    assert isinstance(truck3, Truck)
    assert type(truck3) == Truck
    # check for range implementation
    assert truck1.range() == 5
    assert truck2.range() == 500
    assert truck3.range(3) == 120*60*3


if __name__ == '__main__':
    tests()