public static List <Guid> getGuidanceItemsIds_NotInViews(this TM_WebServices tmWebServices, Guid libraryId)
{
var guidanceInViews = (from view in tmWebServices.GetViews()
where view.libraryId == libraryId
from guidanceItem in view.guidanceItems
select guidanceItem).Distinct().toList();
var guidanceItemsIdsNotInViews = (from guidanceItem in tmWebServices.GetGuidanceItemsInLibrary(libraryId)
where guidanceInViews.contains(guidanceItem.Metadata.Id).isFalse()
select guidanceItem.Metadata.Id).toList();
return(guidanceItemsIdsNotInViews);
}