How to add two or more Google fonts to the font list

In your support page https://docs.generatepress.com/article/customizing-the-google-font-list/ you explain how to add one Google font to the font list.

How would I add two - or more - Google fonts, say the two examples you give: Zilla Slab & David Libre?

I added a new snippet in the same form, but then got the message "Cannot redeclare function za_add_google_fonts." Though I could create a different function name, I would prefer to know how to add them with a single function.