def parse_update_response(body)
        dom = parse_and_validate_response(body, :root_name => 'update')
        dom.root.if_attribute_value(:time) { |v| Time.parse(v) }
      end
def parse_update_response(body)
        dom = parse_and_validate_response(body, :root_name => 'update')
        dom.root.if_attribute_value(:time) { |v| Time.parse(v) }
      end
Parses the response of an Update request
 and returns the update Timestamp.