src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts/NotebookTextModel/_insertNewCell
class NotebookTextModel:	private _insertNewCell(index: number, cells: NotebookCellTextModel[], synchronous: boolean, endSelections: ISelectionState | undefined): void {
		for (let i = 0; i < cells.length; i++) {
			const dirtyStateListener = cells[i].onDidChangeContent((e) => {
				this._bindCellContentHandler(cells[i], e);
			});

			this._cellListeners.set(cells[i].handle, dirtyStateListener);
		}

		const changes: NotebookCellTextModelSplice<ICell>[] = [[index, 0, cells]];
		this._onWillAddRemoveCells.fire({ rawEvent: { kind: NotebookCellsChangeType.ModelChange, changes } });
		this._cells.splice(index, 0, ...cells);
		this._pauseableEmitter.fire({
			rawEvents: [{ kind: NotebookCellsChangeType.ModelChange, changes, transient: false }],
			versionId: this.versionId,
			synchronous: synchronous,
			endSelectionState: endSelections
		});

		return;
	}