src/vs/workbench/contrib/notebook/browser/controller/coreActions.ts/NotebookMultiCellAction/isCellToolbarContext
class NotebookMultiCellAction:	private isCellToolbarContext(context?: unknown): context is INotebookCellToolbarActionContext {
		return !!context && !!(context as INotebookActionContext).notebookEditor && (context as any).$mid === MarshalledId.NotebookCellActionContext;
	}