code: def compare_view(self, request, object_id, version_id, extra_context=None):
          
          opts = self.model._meta
          object_id = unquote(object_id)
          # get_for_object's ordering means this is always the latest revision.
          # The reversion we want to compare to
          current = Version.objects.get_for_object_reference(self.model, object_id)[0]
          revision = Version.objects.get_for_object_reference(self.model, object_id).filter(id=version_id)[0]
  
          the_diff = make_diff(current, revision)
  
          context = {
              "title": _("Comparing current %(model)s with revision created %(date)s") % {
                  'model': current,
                  'date' : get_date(revision),
                  },
              "opts": opts,
              "compare_list_url": reverse("%s:%s_%s_comparelist" % (self.admin_site.name, opts.app_label, opts.model_name),
                                                                    args=(quote(object_id),)),
              "diff_list": the_diff,
          }
  
          extra_context = extra_context or {}
          context.update(extra_context)
          return render(request, self.compare_template or self._get_template_list("compare.html"),
                        context)
docs: Actually compare two versions.