iTop/application/applicationextension/backoffice/AbstractPreferencesExtension.php

<?php

/**
 * Extend this class instead of implementing iPreferencesExtension if you don't need to overload all methods
 *
 * @api
 * @package     PreferencesExtensibilityAPI
 * @since       2.7.0
 */
abstract class AbstractPreferencesExtension implements iPreferencesExtension
{
    /**
     * @inheritDoc
     */
    public function DisplayPreferences(\Combodo\iTop\Application\WebPage\WebPage $oPage)
    {
        // Do nothing
    }

    /**
     * @inheritDoc
     */
    public function ApplyPreferences(\Combodo\iTop\Application\WebPage\WebPage $oPage, $sOperation)
    {
        // Do nothing
    }

}