src/vs/workbench/api/common/extHostNotebook.ts/ExtHostNotebookController/createNotebookDocument
class ExtHostNotebookController:	async createNotebookDocument(options: { viewType: string, content?: vscode.NotebookData }): Promise<URI> {
		const canonicalUri = await this._notebookDocumentsProxy.$tryCreateNotebook({
			viewType: options.viewType,
			content: options.content && typeConverters.NotebookData.from(options.content)
		});
		return URI.revive(canonicalUri);
	}