Method handleCategory

/**
 * Method to handle the `<category>` element for the feed.
 *
 * @param   Feed               $feed  The Feed object being built from the parsed feed.
 * @param   \SimpleXMLElement  $el    The current XML element object to handle.
 *
 * @return  void
 *
 * @since   3.1.4
 */
protected function handleCategory(Feed $feed, \SimpleXMLElement $el)
{
    // Get the data from the element.
    $domain = (string) $el['domain'];
    $category = $this->inputFilter->clean((string) $el, 'html');
    $feed->addCategory($category, $domain);
}