src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts/NotebookEditorWidget/moveCellsToIdx
class NotebookEditorWidget:	async moveCellsToIdx(index: number, length: number, toIdx: number): Promise<ICellViewModel | null> {
		if (!this.viewModel) {
			return null;
		}

		if (this.viewModel.options.isReadOnly) {
			return null;
		}

		return this._moveCellToIndex(index, length, toIdx);
	}