class Car:

    def __init__(self, make, model, year, mpg=25):
        self.make = make
        self.model = model
        self.year = year
        self.mpg = mpg

        self.is_started = False
        self.gas = 0

    def get_car_details(self):
        '''returns the car's specifications as a tuple'''
        return self.make, self.model, self.year, self.mpg

    def start_car(self):
        '''starts the vehicle'''
        self.is_started = True
        print('Started car .. ')

    def add_gas(self, gas):
        '''adds gas to car'''
        self.gas += gas

    def drive(self):
        '''
        line 30 checks if the car is started
        and also checks if gas is not 0 (the car has gas)
        '''
        if not self.is_started:
            print('turn on car first')
        elif not self.gas:
            print('you need to add gas')
        else:
            print('driving to the store')

        if self.gas:
            self.gas -= 1  # driving consumes gas if the car has gas


if __name__ == '__main__':
    audi = Car('audi', 'a8', 2019)

    make, model, year, mpg = audi.get_car_details()
    print(f'make: {make}\nmodel: {model}\nyear: {year}\nmpg: {mpg}')

    print('calling drive')
    audi.drive()

    print('starting car')
    audi.start_car()

    print('calling drive')
    audi.drive()

    print('adding 10 gas')
    audi.add_gas(10)

    print('driving')
    audi.drive()

    print('checking gas')
    print(audi.gas)