code: def crossposted_content(self):
          
          url = "http://{0}{1}".format(self.site.domain, self.get_absolute_url())
          origin = (
              '<p><em>This entry was originally published at: '
              '<a href="{0}">{1}</a>.</em></p>#end'.format(url, url)
          )
          return mark_safe(u"{0}{1}".format(self.content, origin))
docs: Content to be cross-posted on other sites. This method adds an
          additional line of content with a link back to the original site as
          well as the `#end` tag. This signals the end blog content according
          to: https://support.google.com/blogger/answer/41452?hl=en