Decode base64 until flag is found

decode.py

#!usr/bin/env python3

from base64 import b64decode

f = open('lol.txt', 'r')
string = str(f.read())
f.close()

print("Decoding...")
while True:
    try:
        b64str = b64decode(string).decode('utf-8')
        string = b64str
    except:
        print("Done.\n")
        print(f'Decoded string: "{b64str}"')
        break