     ///   - sectionIndex: optional - all insertion/deletion calls will be made on this index.
     public init(tableView: NSTableView?, initialRows: [Value] = [], sectionIndex: Int = 0) {
         self.tableView = tableView
-        self.internalDiffCalculator = TableViewDiffCalculator(tableView: tableView, initialSectionedValues: SingleSectionTableViewDiffCalculator.buildSectionedValues(values: initialRows, sectionIndex: sectionIndex))
+        self.internalDiffCalculator = SectionedTableViewDiffCalculator(tableView: tableView, initialSectionedValues: TableViewDiffCalculator.buildSectionedValues(values: initialRows, sectionIndex: sectionIndex))
         self.sectionIndex = sectionIndex
     }
 

            return self.internalDiffCalculator.sectionedValues[self.sectionIndex].1
        }
        set {
            self.internalDiffCalculator.sectionedValues = SingleSectionTableViewDiffCalculator.buildSectionedValues(values: newValue, sectionIndex: self.sectionIndex)
        }
    }


            return self.internalDiffCalculator.sectionedValues[self.sectionIndex].1
        }
        set {
            self.internalDiffCalculator.sectionedValues = TableViewDiffCalculator.buildSectionedValues(values: newValue, sectionIndex: self.sectionIndex)
        }
    }

