def sign(self, data, fingerprint):
        try:
            pub_key = self.__find_key(fingerprint)

            if not pub_key:
                raise exceptions.SshAgentError(
                    "Your ssh-agent does not have the required key added. This "
                    "usually indicates that ssh-add has not been run.")

            self.sock.send(i2s(len(pub_key) + len(data) + 13) +
                           chr(SSH2_AGENTC_SIGN_REQUEST))
            write_field(self.sock, pub_key)
            write_field(self.sock, data)
            self.sock.send("\0\0\0\0")
            length, response_code, resp_len = struct.unpack("!IBI",
                                                            self.sock.recv(9))
            assert response_code == SSH2_AGENT_SIGN_RESPONSE
            buf = self.sock.recv(5 - length)
            fields = rsa.read_fields(buf)
            response_type = fields.next()
            assert response_type == "ssh-rsa"
            return fields.next()
        except socket.timeout as why:
            raise exceptions.SshAgentError(why)
dataset/ETHPy150Open spotify/crtauth/crtauth/ssh.py/AgentSigner.sign/swapped operands of `-`