def new_keypair(key, value, ambig, unambig):
    """
    Check new keypair against existing unambiguous dict

    :param key: of pair
    :param value: of pair
    :param ambig: set of keys with ambig decoding
    :param unambig: set of keys with unambig decoding
    :return:
    """
    if key in ambig:
        return

    if key in unambig and value != unambig[key]:
            ambig.add(key)
            del unambig[key]
            return

    unambig[key] = value
    return
Check new keypair against existing unambiguous dict

    :param key: of pair
    :param value: of pair
    :param ambig: set of keys with ambig decoding
    :param unambig: set of keys with unambig decoding
    :return: