public function encodeValue(EncodePropertyValueFromWidgetEvent $event)
    {
        if (!$this->wantToHandle($event)) {
            return;
        }

        if (is_array($event->getValue())) {
            $values = [];

            foreach ($event->getValue() as $value) {
                $values[] = substr($value, 6);
            }

            // Cut off the 'value_' prefix.
            $event->setValue($values);
        } else {
            // Cut off the 'value_' prefix.
            $event->setValue(substr($event->getValue(), 6));
        }
    }