:return: Xml for order by property
            :rtype: lxml.etree.Element

def write_xml(self):
        '''
            :return: Xml for order by property
            :rtype: lxml.etree.Element
        '''
        order_by_specs = etree.Element('order-by-property')

        order_by_specs.attrib['type-id'] = self.typeid
        order_by_specs.attrib['property-name'] = self.property_name
        order_by_specs.attrib['direction'] = self.direction
        return order_by_specs