Downloading YouTube Captions with API in Python with utf-8 characters

I'm using Jeff's demo code for using the YouTube API and Python to interact with captions for my videos. And I have it working great for my videos in English. Unfortunately, when I try to use it with my videos that have automatic transcripts in Spanish, which contain characters such as á¡, etc., I get an encoding error:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 25: ordinal not in range(128)

My Python script has # -*- coding: utf-8 -*- at the top and I've changed the CAPTIONS_LANGUAGE_CODE to 'es', but it seems like the script is still interpreting the .srt file it downloads as ascii rather than utf-8. The line where it downloads the .srt file is:

if response_headers["status"] == "200":  self.srt_captions = SubRipFile.from_string(body)

How can I get Python to consider the srt file as utf-8 so that it doesn't throw an encoding error?

Thanks!