public void InsertBatch(IList <Employee> employees)
        {
            if (employees == null || employees.Count == 0)
            {
                throw new ArgumentException($"{nameof(employees)} is null or empty.", nameof(employees));
            }

            using (var db = new OrmCookbook())
            {
                foreach (var employee in employees)
                {
                    db.Insert(employee);
                }
            }
        }