Remove Duplicates Keep Order

Write remove_duplicates_keep_order(values: list[int]) -> list[int] that returns a new list holding each value once, in the order of its first appearance. Walk the list once, keep a set of the values already added (its add() method records one), and append() a value to the result only when it is not yet in the set. Do NOT write a main block or any top-level test code; the tests construct the calls. Input: one line of space-separated integers (possibly empty); the tests print the list your function returns.