def lines_unique_update(lines_list1, lines_list2):
    """update a list of lines with another.

    Only lines not already present are added.

    May raise:
        TypeError if the arguments are not lists.
    """
    if not isinstance(lines_list1, list):
        raise TypeError('not a list: %s' % repr(lines_list1))
    if not isinstance(lines_list2, list):
        raise TypeError('not a list: %s' % repr(lines_list2))
    if not lines_list1:
        lines_list1.extend(lines_list2)
        return
    if not lines_list2:
        return
    s = set(lines_list1)
    for l in lines_list2:
        if l not in s:
            lines_list1.append(l)
