code: def extract(self, item, list_article_candidate):
          
          list_author = []
  
          # The authors of the ArticleCandidates and the respective extractors are saved in a tuple in list_author.
          for article_candidate in list_article_candidate:
              if (article_candidate.author is not None) and (article_candidate.author != '[]'):
                  list_author.append((article_candidate.author, article_candidate.extractor))
  
          # If there is no value in the list, return None.
          if len(list_author) == 0:
              return None
  
          # If there are more options than one, return the result from newspaper.
          list_newspaper = [x for x in list_author if x[1] == "newspaper"]
          if len(list_newspaper) == 0:
  
              # If there is no author extracted by newspaper, return the first result of list_author.
              return list_author[0][0]
          else:
              return list_newspaper[0][0]
docs: Compares the extracted authors.
  
          :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 authors