public function extractXmlToArray(DOMNode $contextNode, array $mapping, DOMXPath $xpath)
    {
        $data = [];
        $coreHelper = Mage::helper('radial_core');
        foreach ($mapping as $key => $callback) {
            if ($callback['type'] !== 'disabled') {
                $result = $xpath->query($callback['xpath'], $contextNode);
                if ($result->length) {
                    $callback['parameters'] = [$result];
                    $data[$key] = $coreHelper->invokeCallback($callback);
                }
            }
        }
        return $data;
    }