This is how it is done in JS:

const obj = Transaction.from(Buffer.from(base64string, 'base64'));

this is how I think it could be done in Python:

import base64

base64string = "<some jibberish>"
decode = base64.b64decode(code)

it produces a byte type thus far. I'm not sure if I'm on the right track here... I've tried using picke.loads to no avail.