def mark_sentence(s, args):
    """Insert markers around relation arguments in word sequence

    :param s: list of tokens in sentence.
    :type s: list
    :param args: list of triples (l, h, idx) as per @_mark(...) corresponding
               to relation arguments
    :type args: list
    :return: The marked sentence.
    :rtype: list

    Example: Then Barack married Michelle.
         ->  Then ~~[[1 Barack 1]]~~ married ~~[[2 Michelle 2]]~~.
    """

    marks = sorted([y for m in args for y in mark(*m)], reverse=True)
    x = list(s)
    for k, v in marks:
        x.insert(k, v)
    return x