$caption = FilteredMarkup::create(Xss::filter($caption, ['a', 'em', 'strong', 'cite', 'code', 'br']));
// The caption must be non-empty.
$caption = FilteredMarkup::create(Xss::filter($caption, ['a', 'em', 'strong', 'cite', 'code', 'br']));
// The caption must be non-empty.