Attributes:
- Model_year (Integer)
- Color (String)
- Miles_per_gallon (float)
- Current_fuel_level (float)
- Fuel_tank_size (Integer)
- Transmission_type (String)
- Current_passengers (integer)
- Passenger_capacity (integer)
Methods:
- Current_gas_percentage: (Current_fuel_level divided by Fuel_tank_size)
- Change_color: (paint car, update Color)
- Seats_remaining: (Passenger_capacity minus Current_passengers)
- Car_age: (Model_year minus current year)
- Add_passenger: (add number of passengers to Current_passengers)