def remove_duplicates(original_list):
    """
    removes duplicate items from original_list, keeping first instance of duplicate
    :param original_list: list that contains duplicate items
    :return: list without duplicate items, keeping the first instance of the duplicated item
    """
    final_list = []
    for item in original_list:
        if item not in final_list:
            final_list.append(item)
    return final_list