runtimequestion 254 Classes & Objects · easy
Allowed order status changes
An order's status may only change along certain paths: a pending order can be paid or cancelled, a paid order shipped, cancelled or refunded, a shipped order delivered or returned, and a delivered order returned. Write Order(order_id) with those rules stored once, on the class, and a method move_to(status) that enforces them and keeps a history.
Class attribute
ALLOWED = {"pending": ["paid", "cancelled"], "paid": ["shipped", "cancelled", "refunded"], "shipped": ["delivered", "returned"], "delivered": ["returned"]}`Order(order_id)`attributes
order_id, status (starts "pending"), history (starts ["pending"])`move_to(status)`changes the status and appends it to history if the move is allowed; otherwise raises
ValueError and changes nothing