private function add_html_special_chars_handler() {
		$this->engine->addHelper(
			'html_special_chars',
			function ( $template, $context, $args ) {
					$that = $context->get( 'this' );

				if ( array_key_exists( $args, $that ) ) {
					return htmlspecialchars( $that[ $args ] );
				}
			}
		);
	}