def is_auxiliary_relation(token1, token2):
    """Return True if `token1` is an auxiliary dependent of `token2`."""
    return (
        (token1.upos == "AUX")
        and (token1.deprel in ["aux", "aux:pass"])
        and (token2.upos == "VERB")
        and (token1.head == token2.id)
    )