def get_indexed_attestation_participants(spec, indexed_att):
    """
    Wrapper around index-attestation to return the list of participant indices, regardless of spec phase.
    """
    if spec.fork == "phase1":
        return list(spec.get_indices_from_committee(
            indexed_att.committee,
            indexed_att.attestation.aggregation_bits,
        ))
    else:
        return list(indexed_att.attesting_indices)