element -- DOM node or document
           parent -- WSDLAdapter instance

def loadFromNode(self, parent, element):
        """element -- DOM node or document
           parent -- WSDLAdapter instance
        """
        reader = self.__readerClass(element)
        schema = XMLSchema(parent)
        #HACK to keep a reference
        schema.wsdl = parent
        schema.setBaseUrl(self.__base_url)
        schema.load(reader)
        return schema