src/vs/workbench/contrib/notebook/browser/viewModel/notebookViewModel.ts/NotebookViewModel/createCell
class NotebookViewModel:	createCell(index: number, source: string, language: string, type: CellKind, metadata: NotebookCellMetadata | undefined, outputs: IOutputDto[], synchronous: boolean, pushUndoStop: boolean = true, previouslyPrimary: number | null = null, previouslyFocused: ICellViewModel[] = []): CellViewModel {
		const beforeSelections = previouslyFocused.map(e => e.handle);
		const endSelections: ISelectionState = { kind: SelectionStateType.Index, focus: { start: index, end: index + 1 }, selections: [{ start: index, end: index + 1 }] };
		this._notebook.applyEdits([
			{
				editType: CellEditType.Replace,
				index,
				count: 0,
				cells: [
					{
						cellKind: type,
						language: language,
						mime: undefined,
						outputs: outputs,
						metadata: metadata,
						source: source
					}
				]
			}
		], synchronous, { kind: SelectionStateType.Handle, primary: previouslyPrimary, selections: beforeSelections }, () => endSelections, undefined);
		return this._viewCells[index];
	}