Encodes and decodes "Gödel Numbers" as described in the book "Gödel's Proof" by Ernest Nagel and James R. Newman.

import godel

gnum = godel.encode('(∃x)(x=sy)')

self.assertEqual(gnum, 172225505803959398742621651659678877886965404082311908389214945877004912002249920215937500000000)

string = godel.decode(172225505803959398742621651659678877886965404082311908389214945877004912002249920215937500000000)

self.assertEqual(string, '(∃x)(x=sy)')