code: def body_class_tag(context):
      
      request = context.get("request")
      if not hasattr(request, "ROUTE"):
          return ""
  
      css_classes = []
  
      namespace = request.ROUTE["namespace"]
      if namespace:
          namespace = RE_CLEAN_CSS_NAME.sub("-", namespace.lower())
          css_classes.append("ns-{}".format(namespace))
  
      view = request.ROUTE["url_name"]  # Use ``url_name`` as ``view_name`` includes the namespace.
      if view:
          view = RE_CLEAN_CSS_NAME.sub("-", view.lower())
          css_classes.append("vw-{}".format(view))
  
      return " ".join(css_classes)
docs: Return CSS "class" attributes for <body>.
  
      Allows to provide a CSS namespace using urlpatterns namespace (as ``.ns-*``) and view name (as ``.vw-*``).
  
      Usage: ``{% body_class %}``
      Example: ``ns-my-app vw-my-view`` or ``ns-contacts vw-list``
      Requires: ``apps.core.middlewares.CoreMiddleware``.