def METHOD_NAME(db_session, user_vetinari):
    """Add main notification preferences for user_vetinari."""
    prefs = models.NotificationPreferences(
        notification_type='',
        account=user_vetinari,
        by_email=True,
        by_sms=True,
        by_webpush=True,
        by_telegram=True,
        by_whatsapp=True,
    )
    db_session.add(prefs)
    db_session.commit()
    return prefs