def str_to_set(str_mention):
    """
    input: mention in str format ("sentence_id[indices_ids]")
    output: set of 1-index strs ("sentence_id[index_id]","sentence_id[index_id]","sentence_id[index_id]")
    """
    sent = str_mention.split('[')[0]
    indices = str_mention[str_mention.index('[') + 1 : str_mention.index(']')].split(',')
    return set([sent + '[' + index + ']' for index in indices])