title: Unable to scrape while running scrapy spider sequentially
body: <p>I'm new to scrapy and I'm trying to practice with and example, I want to run scrapy spiders sequentially but when I use the code from the documentation
  (<a href="https://doc.scrapy.org/en/latest/topics/practices.html#run-scrapy-from-a-script" rel="nofollow noreferrer">https://doc.scrapy.org/en/latest/topics/practices.html#run-scrapy-from-a-script</a>) while using crawler process it doesn't work. The spiders opens and close instantly without scraping data from the website. But when I run the spiders alone using "scrapy crawl" it works. I don't understand why spider scrape datas while I call it alone and doesn't scrape datas while I try to run it sequentially. If someone could help me with that it would be great. 
  Here's the code that I'm using:</p>
  
  <pre><code>class APASpider(scrapy.Spider):
  name = 'APA_test'
  allowed_domains = ['some_domain.com']
  start_urls = ['startin_url']
  
  
  
  def start_requests(self):
      for url in self.start_urls:
          yield SplashRequest(url, self.parse,
          endpoint='execute',
          cache_args=['lua_source'],
          args={'lua_source': script,'timeout': 3600},
          headers={'X-My-Header': 'value'},
          )
  
  def parse(self, response):
  
      for href in response.xpath('//a[@class="product-link"]/@href').extract():            
          yield SplashRequest(response.urljoin(href),self.parse_produits,
          endpoint='execute',
          cache_args=['lua_source'],
          args={'lua_source': script,'timeout': 3600},
          headers={'X-My-Header': 'value'},
          )
  
  
      for pages in response.xpath('//*[@id="loadmore"]/@href'):
          yield SplashRequest(response.urljoin(pages.extract()),self.parse,
          endpoint='execute',
          cache_args=['lua_source'],
          args={'lua_source': script,'timeout': 3600},
          headers={'X-My-Header': 'value'},
          )
  
  
  
  def parse_produits(self,response):
  
      Nom = response.xpath("//h1/text()").extract()
      Poids = response.xpath('//p[@class="description"]/text()').extract()
      item_APA = APAitem()
      item_APA["Titre"] = Nom
      item_APA["Poids"] = Poids
      yield item_APA
  
  configure_logging()
  runner = CrawlerRunner()
  
  
  @defer.inlineCallbacks
  def crawl():
  yield runner.crawl(APASpider)
  reactor.stop()
  
  crawl()
  reactor.run() # the script will block here until the last crawl call is finished
  </code></pre>
  
  <p>Thank you</p>