public function getThemes()
    {
        $json = $this->container->json;

        if (null === $definition = $json->getJson(ROOT_DIR . 'structure/definitions/themes.json', 'themes')) {
            throw new Exception('PitonCMS: Get themes exception: ' . implode($json->getErrorMessages(), ','));
        }

        return array_column($definition->themes, 'name', 'value');
    }