    def get_layer(self, request):
        """
        This method is used to get the layer of the admin interface.
        """
        _action = request.POST.get("_action")
        if hasattr(self, _action):
            func, action, description = self.get_action(_action)
            if hasattr(func, "layer"):
                arg_count = func.layer.__code__.co_argcount
                if arg_count == 2:
                    result = func.layer(self, request)
                elif arg_count == 3:
                    # 兼容老版本
                    qs = self._get_queryset(request)
                    result = func.layer(self, request, qs)

                return JsonResponse(data=result, safe=False)
        else:
            raise Exception(f'action "{_action}" not found')
This method is used to get the layer of the admin interface.
simpleui/admin.py