src/vs/workbench/api/common/extHostNotebookKernels.ts/ExtHostNotebookKernels/$acceptNotebookAssociation
class ExtHostNotebookKernels:	$acceptNotebookAssociation(handle: number, uri: UriComponents, value: boolean): void {
		const obj = this._kernelData.get(handle);
		if (obj) {
			// update data structure
			const notebook = this._extHostNotebook.getNotebookDocument(URI.revive(uri))!;
			if (value) {
				obj.associatedNotebooks.set(notebook.uri, true);
			} else {
				obj.associatedNotebooks.delete(notebook.uri);
			}
			this._logService.trace(`NotebookController[${handle}] ASSOCIATE notebook`, notebook.uri.toString(), value);
			// send event
			obj.onDidChangeSelection.fire({
				selected: value,
				notebook: notebook.apiNotebook
			});
		}
	}