def contsignlist_to_txt(contsigns, txt_path=None):
    """contsignlist to txt file."""
    import random
    if txt_path is None:
        txt_path = '/tmp/contsigns_to_kv.tmp.' + str(random.randint(0, 100000))
    with open(txt_path, 'wb') as fout:
        fout.write('\n'.join(contsigns))
    return txt_path
