Add visualizations for mutable objects in [6.3.9. Mutable Versus Immutable Parameters](https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2F632bfb89f4b1954b460397a0--epic-agnesi-957267.netlify.app%2Foop_intro.html%23mutable-versus-immutable-parameters&data=05%7C01%7Cu6474961%40anu.edu.au%7C1f2c6d9cfaca409ff42808daa0d768ff%7Ce37d725cab5c46249ae5f0533e486437%7C0%7C0%7C637999144286179761%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=RtY9hxV1IRAWl1JaGiD%2F9smaSaiO02%2F5gnHbzbAq0yo%3D&reserved=0) using `%nbtutor`.