title: AttributeError: 'set' object has no attribute 'iteritems'
body: <p>I was scrapy with python2.7 </p>
  
  <p>then this happened:</p>
  
  <p><img src="https://i.stack.imgur.com/iASwE.png" alt="Errorcode"></p>
  
  <p><img src="https://i.stack.imgur.com/6rYqC.png" alt="Spider(I will not mention Domain.)"></p>
  
  <p>Plase help me, Thank you</p>