def schedule_next_request(self):
        """ Schedules a request, if exists.

        :return:
        """
        req = self.next_request()

        if req:
            self.crawler.engine.crawl(req, spider=self)
def schedule_next_request ( self ) : req = self . next_request ( ) if req : self . crawler . engine . crawl ( req , spider = self )
Schedules a request, if exists.

        :return: