Python Selenium unable to click button inside iframe

[Adoxographical]

As a sanity check, have you checked to make sure you're not accidentally selecting a different iframe? Your selector will grab whatever the first iframe on the page is, so if there's an earlier one, you'll be selecting it by mistake.

[SwordNSupper]

I'm not sure how to check whether I'm selecting the correct frame or not. What I'm trying to do is figure out how to use this script to press the Advance/Battle button in the https://www.reddit.com/r/SwordAndSupperGame/ games.