Translate Text using gettext filter/hook

<?php

/**
 * Translate Text using gettext filter/hook
 * As for where to paste this : http://wp-events-plugin.com/tutorials/how-to-safely-add-php-code-to-wordpress/
 */
function change_label( $translated_text, $text, $domain ) {
        switch ( $translated_text ) {
            case 'Do you already have an account with us? %' :
                $translated_text = 'Hai già un account con noi? %';
                break;
            case 'You do not have the rights to manage this event.' :
                $translated_text = 'Non hai i diritti per gestire questo evento.';
                break;
            case 'Unauthorized Access' :
                $translated_text = 'Accesso non autorizzato';
                break;
            case 'Add To Calendar' :
                $translated_text = 'Aggiungi al calendario';
                break;

        }
    return $translated_text;
}
add_filter( 'gettext', 'change_label', 100, 3 );