public static function fromXML($xml)
    {
        $dom = new DOMDocument();
        $dom->loadXML($xml);
        $xpath = new DOMXPath($dom);
        $response = $xpath->query("//*[local-name()='GetCompetitivePricingForSKUResponse']");
        if ($response->length == 1) {
            return new MarketplaceWebServiceProducts_Model_GetCompetitivePricingForSKUResponse(($response->item(0)));
        } else {
            throw new Exception ("Unable to construct MarketplaceWebServiceProducts_Model_GetCompetitivePricingForSKUResponse from provided XML. 
                                  Make sure that GetCompetitivePricingForSKUResponse is a root element");
        }
    }