I want to know how to input instance-identifier

It’s as flows.

notification data-changed-notification {
    description "Data change notification.";
    list data-change-event {
        key noti-path;
        leaf noti-path {
            type instance-identifier;
        }
        leaf noti-store {
            type enumeration {
                enum config {
                    tailf:code-name data-changed-config;
                }
                enum operation {
                    tailf:code-name data-changed-operation;
                }
            }
        }
        leaf noti-operation {
            type enumeration {
                enum created {
                    tailf:code-name data-changed-created;
                }
                enum updated {
                    tailf:code-name data-changed-updated;
                }
                enum deleted {
                    tailf:code-name data-changed-deleted;
                }
            }
        }
        anyxml noti-data{
            description "DataObject ";
        }
     }
}