public DepartmentCloneable(string name, DepartmentCloneable parent)
{
Name = name ?? throw new ArgumentNullException(nameof(name));
Parent = parent;
}
public EmployeeCloneable(string name, DepartmentCloneable department)
{
Name = name ?? throw new ArgumentNullException(nameof(name));
Department = department ?? throw new ArgumentNullException(nameof(department));
}