def METHOD_NAME():
    user = create_new_user()
    PartnerUser.create(
        partner_id=get_proton_partner().id,
        user_id=user.id,
        external_user_id=random_token(10),
        flush=True,
    )
    user.trial_end = None
    default_domain = SLDomain.filter_by(
        hidden=False, partner_id=None, premium_only=False
    ).first()
    user.default_alias_public_domain_id = default_domain.id
    Session.flush()
    options = AliasOptions(
        show_sl_domains=False, show_partner_domains=get_proton_partner()
    )
    suffixes = get_alias_suffixes(user, alias_options=options)
    assert suffixes[0].domain == default_domain.domain