code: def _push(self, title, view, class_name, is_class, **kwargs):
          set_view_attr(view, "title", title, cls_name=class_name)
          module_name = view.__module__
          method_name = view.__name__
          _endpoint = build_endpoint_route_name(view, "index" if is_class else method_name, class_name)
          endpoint = kwargs.pop("endpoint", _endpoint)
          kwargs.setdefault("endpoint_kwargs", {})
          order = kwargs.pop("order", 0)
          _nav_tags = get_view_attr(view, "nav_tags", ["default"], cls_name=class_name)
          tags = kwargs.pop("tags", _nav_tags)
          if not isinstance(tags, list):
              _ = tags
              tags = [_]
          kwargs["tags"] = tags
          visible = kwargs.pop("visible", [True])
          if not isinstance(visible, list):
              visible = [visible]
          if get_view_attr(view, "nav_visible", cls_name=class_name) is False:
              visible = False
          kwargs["view"] = view
          kwargs["visible"] = visible
          kwargs["active"] = False
          kwargs["key"] = class_name
          if is_class:
              kwargs["endpoint"] = endpoint
              kwargs["has_subnav"] = True
          else:
              kwargs["has_subnav"] = False
              kwargs.update({
                  "order": order,
                  "has_subnav": False,
                  "title": title,
                  "endpoint": endpoint,
              })
          self._title_map[endpoint] = title
          path = "%s.%s" % (module_name, method_name if is_class else class_name)
          attach_to = kwargs.pop("attach_to", [])
          if not attach_to:
              attach_to.append(path)
          for path in attach_to:
              if path not in self.MENU:
                  self.MENU[path] = {
                      "title": None,
                      "endpoint": None,
                      "endpoint_kwargs": {},
                      "order": None,
                      "subnav": [],
                      "kwargs": {}
                  }
              if is_class:
                  self.MENU[path]["title"] = title
                  self.MENU[path]["order"] = order
                  self.MENU[path]["kwargs"] = kwargs
              else:
                  self.MENU[path]["subnav"].append(kwargs)