src/vs/workbench/contrib/notebook/browser/services/notebookExecutionStateServiceImpl.ts/NotebookExecutionStateService/getLastFailedCellForNotebook
class NotebookExecutionStateService:	getLastFailedCellForNotebook(notebook: URI): number | undefined {
		const failedCell = this._lastFailedCells.get(notebook);
		return failedCell?.visible ? failedCell.cellHandle : undefined;
	}