code: func (auup *AuthUserUserPermission) Update(db XODB) error {
  	var err error
  
  	// if doesn't exist, bail
  	if !auup._exists {
  		return errors.New("update failed: does not exist")
  	}
  
  	// if deleted, bail
  	if auup._deleted {
  		return errors.New("update failed: marked for deletion")
  	}
  
  	// sql query
  	const sqlstr = `UPDATE django.auth_user_user_permissions SET ` +
  		`user_id = ?, permission_id = ?` +
  		` WHERE id = ?`
  
  	// run query
  	XOLog(sqlstr, auup.UserID, auup.PermissionID, auup.ID)
  	_, err = db.Exec(sqlstr, auup.UserID, auup.PermissionID, auup.ID)
  	return err
  }
docs: // Update updates the AuthUserUserPermission in the database.