def _sro_relates(sro, id_):
    """
    Determine whether the given SRO relates an object with the given ID to
    any other object.

    :param sro: An SRO
    :param id_: A STIX ID
    :return: True if SRO relates id_ to something; False if not
    """
    sro_type = sro["type"]
    if sro_type == "relationship":
        relates = id_ in (sro["source_ref"], sro["target_ref"])

    else:
        # sightings
        relates = id_ == sro["sighting_of_ref"] \
            or id_ in sro.get("observed_data_refs", []) \
            or id_ in sro.get("where_sighted_refs", [])

    return relates