def combine_two_lists_no_duplicate(list_1, list_2):
    """
    Method to combine two lists, drop one copy of the elements present in both and return a list comprised of the
    elements present in either list - but with only one copy of each.

    Args:
        list_1: First list
        list_2: Second list
    Returns:
        The combined list, as described above
    """

    additional_unique_elements_list_2 = [i for i in list_2 if i not in list_1]
    return list_1 + additional_unique_elements_list_2