Fix MOO tutorial (#2509)

Summary:
This broke in strange ways in the last PR, after modifying it using the VSCode editor. Updated & verified that it opens using OSS jupyter notebook.

Pull Request resolved: #2509

Reviewed By: Balandat

Differential Revision: D58385728

Pulled By: saitcakmak

fbshipit-source-id: a40d496b1b4d4f8e41bf2527e9eeeb6b5c4aa16e

Author: saitcakmak