public function reverseTransform($content)
    {
        if (null === $content) {
            return null;
        }

        if (!is_string($content)) {
            throw new TransformationFailedException(sprintf(
                'Expected string, %s given',
                gettype($content)
            ));
        }

        //replace span with comment tag, so no weird style is added on front-end
        $content = StripTagsUtil::replaceSpanWith($content, StripTagsUtil::COMMENT_REPLACEMENT);

        return $content;
    }