"base64,BASESTRING"

"base,

"

def bdec(word):
    base64.decode(word, outbase)
    outbase = outbase.decode('utf8')
    outbase = outbase.strip("'")[1]
    return outbase

base = re.compile(r'base64,(?P<grp>.*?)"')
soup=re.sub(base, bdec(grp), soup)

for match in re.findall(base, soup):
     soup=soup.replace(match, bdec(grp))