Implement an Order Composed of Line Items

You will implement two classes: LineItem and Order. A LineItem represents a single product entry with a name, quantity, unit price, and whether it's taxable. An Order is composed of multiple LineItem instances and provides methods to manage items and compute order-level information. Specifically, implement: - LineItem(name: str, quantity: int, unit_price: float, taxable: bool = False) - Order(items: list[LineItem] | None = None) Order methods to implement: - add_item(item: LineItem) -> None : add a LineItem to the order - remove_item(name: str) -> bool : remove the first LineItem with the given name; return True if removed else False - total() -> float : return the sum of quantity * unit_price for all items - total_with_tax(tax_rate: float) -> float : apply tax_rate (e.g., 0.1 for 10%) only to taxable items and return total + tax - most_expensive_item_name() -> str | None : return the name of the item with the highest unit_price, or None if order is empty Write clean, idiomatic Python and make sure the methods behave sensibly for edge cases (empty order, removing non-existent items).

Implement LineItem and Order classes to practice composition: adding/removing items, computing totals, tax application, and querying the most expensive item.

- Do not use external libraries. - Keep numeric calculations precise by using simple fractions (0.5, 1.0) to avoid floating-point surprises in tests. - Methods should handle empty orders and attempts to remove missing items gracefully.