src/vs/workbench/contrib/notebook/browser/services/notebookExecutionStateServiceImpl.ts/NotebookExecutionStateService/getCellExecutionsByHandleForNotebook
class NotebookExecutionStateService:	getCellExecutionsByHandleForNotebook(notebook: URI): Map<number, INotebookCellExecution> | undefined {
		const exeMap = this._executions.get(notebook);
		return withNullAsUndefined(exeMap);
	}