如何在保留订单的同时从列表中删除重复项？

def remove_duplicates(orders):
    return list(set(orders))

def remove_duplicates(orders):
    return list(dict.fromkeys(orders))

def remove_duplicates(orders):
    return [order for i, order in enumerate(orders) if order not in orders[:i]]

def remove_duplicates(orders):
    unique_orders = []
    for order in orders:
        if order not in unique_orders:
            unique_orders.append(order)
    return unique_orders