def remove_duplicates(items):
    """
    Returns a list without duplicates, keeping elements order

    :param items: A list of items
    :return: The list without duplicates, in the same order
    """
    if items is None:
        return items
    new_list = []
    for item in items:
        if item not in new_list:
            new_list.append(item)
    return new_list
