docs: def server_identity_is_verified(self):
          """ GPGAuth stage0 """
          # Encrypt a uuid token for the server
          server_verify_token = self.gpg.encrypt(self._nonce0,
                                                 self.server_fingerprint, always_trust=True)
          if not server_verify_token.ok:
              raise GPGAuthStage0Exception(
                  'Encryption of the nonce0 (%s) '
                  'to the server fingerprint (%s) failed.' %
                  (self._nonce0, self.server_fingerprint)
              )
  
          server_verify_response = post_server_verify_token(
              self,
              keyid=self.user_fingerprint,
              server_verify_token=str(server_verify_token)
          )
  
          if not check_server_verify_response(server_verify_response):
              raise GPGAuthStage0Exception("Verify endpoint wrongly formatted")
  
          if server_verify_response.headers.get('X-GPGAuth-Verify-Response') != self._nonce0:
              raise GPGAuthStage0Exception(
                  'The server decrypted something different than what we sent '
                  '(%s <> %s)' %
                  (server_verify_response.headers.get('X-GPGAuth-Verify-Response'), self._nonce0))
          logger.info('server_identity_is_verified: OK')
          return True