type Parkinglot struct{ id address entrance exit parkingfloor }
type parkingfloor struct{ id floor no slots display }
type entrance struct{ id }
type exit struct{ id }
type slots struct{ id slottype isfull
}
type display struct{ avaiableslots }
type slottype struct{ car iota byke }
type vehicle struct{ registration vehicletype color }# parking_lot_golang