Python3.9 - AttributeError: module 'base64' has no attribute 'decodestring'

Whilst doing a ctf challenge, I needed to brute-force an encrypted private key, so I turned to John and ran the usual

python sshng2john.py hash.txt

This time, however, I was greeted with an unfriendly

> AttributeError: module 'base64' has no attribute 'decodestring'

After some searching around, I realized that I could change Line 640 in sshng2john.py from

data = base64.decodestring(data)

to

data = base64.decodebytes(data)

Which solved the issue.

Silly Python3.9 breaking changes :(