docs: def render_breadcrumbs(context, *args):
      """
      Render breadcrumbs html using bootstrap css classes.
      """
  
      try:
          template_path = args[0]
      except IndexError:
          template_path = getattr(settings, 'BREADCRUMBS_TEMPLATE',
                                  'django_bootstrap_breadcrumbs/bootstrap2.html')
  
      links = []
      for (label, viewname, view_args, view_kwargs) in context[
              'request'].META.get(CONTEXT_KEY, []):
          if isinstance(viewname, Model) and hasattr(
                  viewname, 'get_absolute_url') and ismethod(
                  viewname.get_absolute_url):
              url = viewname.get_absolute_url(*view_args, **view_kwargs)
          else:
              try:
                  try:
                      # 'resolver_match' introduced in Django 1.5
                      current_app = context['request'].resolver_match.namespace
                  except AttributeError:
                      try:
                          resolver_match = resolve(context['request'].path)
                          current_app = resolver_match.namespace
                      except Resolver404:
                          current_app = None
                  url = reverse(viewname=viewname, args=view_args,
                                kwargs=view_kwargs, current_app=current_app)
              except NoReverseMatch:
                  url = viewname
          links.append((url, smart_text(label) if label else label))
  
      if not links:
          return ''
  
      if VERSION > (1, 8):  # pragma: nocover
          # RequestContext is deprecated in recent django
          # https://docs.djangoproject.com/en/1.10/ref/templates/upgrading/
          context = context.flatten()
  
      context['breadcrumbs'] = links
      context['breadcrumbs_total'] = len(links)
  
      return mark_safe(template.loader.render_to_string(template_path, context))