public function confirmMediaType($uriRetriever, $uri)
    {
        $contentType = $uriRetriever->getContentType();

        if (is_null($contentType)) {
            // Well, we didn't get an invalid one
            return;
        }

        if (in_array($contentType, array(Validator::SCHEMA_MEDIA_TYPE, 'application/json'))) {
            return;
        }

        foreach ($this->allowedInvalidContentTypeEndpoints as $endpoint) {
            if (strpos($uri, $endpoint) === 0) {
                return true;
            }
        }

        throw new InvalidSchemaMediaTypeException(sprintf('Media type %s expected', Validator::SCHEMA_MEDIA_TYPE));
    }