code: def insert_read_more_link(instance):
      
  
      # only deals with Article type
      if type(instance) != contents.Article: return
  
  
      SUMMARY_MAX_LENGTH = instance.settings.get('SUMMARY_MAX_LENGTH')
      READ_MORE_LINK = instance.settings.get('READ_MORE_LINK', None)
      READ_MORE_LINK_FORMAT = instance.settings.get('READ_MORE_LINK_FORMAT',
                                                    '<a class="read-more" href="/{url}">{text}</a>')
  
      if not (SUMMARY_MAX_LENGTH and READ_MORE_LINK and READ_MORE_LINK_FORMAT): return
  
      if hasattr(instance, '_summary') and instance._summary:
          summary = instance._summary
      else:
          summary = truncate_html_words(instance.content, SUMMARY_MAX_LENGTH)
  
      if summary != instance.content:
          read_more_link = READ_MORE_LINK_FORMAT.format(url=instance.url, text=READ_MORE_LINK)
          instance._summary = insert_into_last_element(summary, read_more_link)
docs: Insert an inline "read more" link into the last element of the summary
      :param instance:
      :return: