'Processes url stream handler, makes sure it is correct type.'

def ProcessUrlStreamHandlerNode(self, node):

    new_type = node.text
    urlfetch = self.app_engine_web_xml.URL_HANDLER_URLFETCH
    native = self.app_engine_web_xml.URL_HANDLER_NATIVE
    if (new_type not in (urlfetch, native)):
        exception_str = ('url-stream-handler    must    be    %s    or    %s    given    %s' % (urlfetch, native, new_type))
        self.errors.append(exception_str)
    self.app_engine_web_xml.url_stream_handler_type = new_type
