partial         void CopyExtraPropertiesToClone(PicklistCollection clone, bool includeLocalProperties);
 public PicklistCollection Clone(bool includeLocalProperties)
 {
     var c = new PicklistCollection
             {
                 Text = Text,
                 Items = Items.Select(x=>x.Clone(includeLocalProperties)).ToList(),
             };
     CopyExtraPropertiesToClone(c, includeLocalProperties);
     return c;
 }