* Given an array of ('attributename' => 'value'), it generates the code
* to set the XML attributes : attributename="value".
* The values are passed to Sanitizer::encodeAttribute.
- * Return null if no attributes given.
- * @param array $attribs Array of attributes for an XML element
+ * Returns null or empty string if no attributes given.
+ * @param array|null $attribs Array of attributes for an XML element
* @throws MWException
* @return null|string
*/