The example shown in the Wikis API documentation Retrieving and modifying the content of an article is misleading.
The example shows the following:
article = wiki.get_article("article_name")
Instead it should show:
article = wiki.get_article("1")
This is because the argument for get_article() is the article's ID (which appear to be only numbers), not its name.
Also would be good to note how to find the ID (e.g., hover over name on Timeline).