let data = [
            {
                id: 1,
                level: 1,
                children: [
                    {
                        id: 2,
                        level: 2,
                    }
                ]
            },
            {
                id: 3,
                level: 1,
                children: [
                    {
                        id: 4,
                        level: 2,
                    }
                ]
            }
        ];