import urlparse
url = 'https://x...content-available-to-author-only...k.ru/?code=884gdczv72ka3kkco6sxoen2ugp380y1&state=&domain=xxx.omsk.ru'
parsed = urlparse.urlparse(url)
print(urlparse.parse_qs(parsed.query)['code'])
aW1wb3J0IHVybHBhcnNlCnVybCA9ICdodHRwczovL3guLi5jb250ZW50LWF2YWlsYWJsZS10by1hdXRob3Itb25seS4uLmsucnUvP2NvZGU9ODg0Z2RjenY3MmthM2trY282c3hvZW4ydWdwMzgweTEmc3RhdGU9JmRvbWFpbj14eHgub21zay5ydScKcGFyc2VkID0gdXJscGFyc2UudXJscGFyc2UodXJsKQpwcmludCh1cmxwYXJzZS5wYXJzZV9xcyhwYXJzZWQucXVlcnkpWydjb2RlJ10p