code: def extract(self, item, list_article_candidate):
          
          list_description = []
  
          """ The descriptions of the article candidates and the respective extractors are saved
          in a tuple in list_description.
          """
          for article_candidate in list_article_candidate:
              if article_candidate.description != None:
                  list_description.append((article_candidate.description, article_candidate.extractor))
  
          # If there is no value in the list, return None.
          if len(list_description) == 0:
              return None
  
          # If there are more options than one, return the result from newspaper.
          list_newspaper = [x for x in list_description if x[1] == "newspaper"]
          if len(list_newspaper) == 0:
  
              # If there is no description extracted by newspaper, return the first result of list_description.
              return list_description[0][0]
          else:
              return list_newspaper[0][0]
docs: Compares the extracted descriptions.
  
          :param item: The corresponding NewscrawlerItem
          :param list_article_candidate: A list, the list of ArticleCandidate-Objects which have been extracted
          :return: A string, the most likely description