Codigo python

Este es un codigo python para la libre dispociscion de todos:
Lo que tiene un error en desarrollo del objecto entre tanto corrigo el error Os muestro el codigo primario:
import gnupg
from pprint import pprint
class keys(object):
self = []
self.gpg = gnupg.GPG(gnupghome='/home/anon/.gnupg')
def listkeys(self):
public_keys = self.gpg.list_keys()
private_keys = self.gpg.list_keys(True)
print 'public keys:'
pprint(public_keys)
print 'private keys:'
pprint(private_keys)
print 'resumen:'
#falta hacer un buscador
def encrytar(self, a, b):
unencrypted_string = a
encrypted_data = self.gpg.encrypt(unencrypted_string, b)
encrypted_string = str(encrypted_data)
print 'ok: ', encrypted_data.ok
print 'status: ', encrypted_data.status
print 'stderr: ', encrypted_data.stderr
print 'unencrypted_string: ', unencrypted_string
print 'encrypted_string: ', encrypted_string
return encrypted_string
def descrytar(self, a, b, c):
unencrypted_string = a
encrypted_data = self.gpg.encrypt(unencrypted_string, b)
encrypted_string = str(encrypted_data)
decrypted_data = self.gpg.decrypt(encrypted_string, passphrase=c)
print 'ok: ', decrypted_data.ok
print 'status: ', decrypted_data.status
print 'stderr: ', decrypted_data.stderr
print 'decrypted string: ', decrypted_data.data
return decrypted_data.data