code: def dispatch_item_id!(iid)
        type = iid.keys.first
        item = iid[type]
        case type
        when :item_id
          item_id!(item)
        when :occurrence_item_id
          occurrence_item_id!(item)
        when :recurring_master_item_id
          recurring_master_item_id!(item)
        else
          raise EwsBadArgumentError, "Bad ItemId type. #{type}"
        end
      end
docs: A helper method to dispatch to an ItemId, OccurrenceItemId, or a RecurringMasterItemId
   @param [Hash] iid The item id of some type