old_contents: #!/usr/bin/env python
  import json
  
  import scrapper
  
  
  def get_image(value, content, response):
      try:
          mapping = json.loads(value['data-a-dynamic-image'])
          mapping = {d[0] * d[1]: url for url, d in mapping.items()}
          return mapping[max(mapping.keys())]
      except (KeyError, ValueError, TypeError):
          return None
  
  
  class AmazonEntry(scrapper.CrawlerItem):
      title = scrapper.CrawlerField('#productTitle')
      price = scrapper.CrawlerField(
          'div.feature span.a-color-price',
          lambda value, content, response: value.strip(),
      )
      img = scrapper.CrawlerField(
          '#imgTagWrapperId img.a-dynamic-image',
          get_image,
          True,
      )
  
  
  links = [
      'http://www.amazon.co.uk/Lenovo-ThinkPad-T430s-i5-3320M-N1RLQGE/dp/'
      'B00AQPBA8U/ref=sr_1_1?ie=UTF8&qid=1449485817&sr=8-1&keywords=t430s',
      'http://www.amazon.co.uk/Lenovo-ThinkPad-T430s-23539WU-Notebook/dp/'
      'B009UESY2I/ref=pd_sim_sbs_147_4?ie=UTF8&dpID=41ZwThpTAOL&dpSrc=sims'
      '&preST=_AC_UL160_SR160%2C160_&refRID=1MQ4F7Y27EX36HCAPMP8',
      'http://www.amazon.co.uk/Lenovo-Thinkpad-14-inch-i5-2520M-Professional'
      '/dp/B004WNAYS4/',
  ]
  
  for link in links:
      product = AmazonEntry(link)
  
      print 'title: %s\nprice: %s\nimg:%s' % (
          product.title, product.price, product.img,
      )
  
new_contents: #!/usr/bin/env python
  import json
  
  import scrapper
  
  
  def get_image(value, content, response):
      try:
          mapping = json.loads(value['data-a-dynamic-image'])
          mapping = {d[0] * d[1]: url for url, d in mapping.items()}
          return mapping[max(mapping.keys())]
      except (KeyError, ValueError, TypeError):
          return None
  
  
  class AmazonEntry(scrapper.CrawlerItem):
      title = scrapper.CrawlerField('#productTitle')
      price = scrapper.CrawlerField(
          'div.feature span.a-color-price',
          lambda value, content, response: value.strip(),
      )
      img = scrapper.CrawlerField(
          '#imgTagWrapperId img.a-dynamic-image',
          get_image,
          True,
      )
  
  
  links = [
      'http://www.amazon.co.uk/Lenovo-ThinkPad-T430s-i5-3320M-N1RLQGE/dp/'
      'B00AQPBA8U/ref=sr_1_1?ie=UTF8&qid=1449485817&sr=8-1&keywords=t430s',
      'http://www.amazon.co.uk/Lenovo-ThinkPad-T430s-23539WU-Notebook/dp/'
      'B009UESY2I/ref=pd_sim_sbs_147_4?ie=UTF8&dpID=41ZwThpTAOL&dpSrc=sims'
      '&preST=_AC_UL160_SR160%2C160_&refRID=1MQ4F7Y27EX36HCAPMP8',
      'http://www.amazon.co.uk/Lenovo-Thinkpad-14-inch-i5-2520M-Professional'
      '/dp/B004WNAYS4/',
  ]
  
  products = [AmazonEntry(link) for link in links]
  for product in products:
      print 'title: %s\nprice: %s\nimg:%s' % (
          product.title, product.price, product.img,
      )
  
subject: Change of one of example