db = new DatabaseManager(...);
car = new Car(owner=db.get(name="john smith"), brand="honda", model="...", color="silver_60%")
car.parts.add(new Part(type="bumper", brand="honda"), job_type=Part.replace_to_new)
car.parts.add(new Part(type="audio", brand="sony"), job_type=Part.add_new)
car.parts.add(new Part(type="engine", brand="honda"), job_type=Part.fix)
db.save(car)
print car.parts[0]
db.close()