code: function Server(config) {
          RED.nodes.createNode(this, config);
  
          // Start a DLPA server.
          // Options:
          //   --port PORT           Listening port number.
          //   --clients CLIENTS     The number of clicents.
          //   --max-workers MAX_WORKERS
          //                         The maximum number of workiers (default: 10).
          const proc = spawn("python3", [
              "-m", "dlpa.server",
              "--port", config.port,
              "--clients", config.nclient,
              "--key-length", "128",
              "--time-span", config.span ? config.span : "300"
          ], {
              cwd: __dirname,
          });
          let exited = false;
          proc.on("exit", (code, signal) => {
              this.log(`DLPA server is closed: ${signal}`);
              exited = true;
          })
          const logger = readline.createInterface({
              input: proc.stderr
          });
          logger.on("line", (line) => {
              this.log(line);
          })
  
          // Wait results which should be outputted into stderr; and then
          // post a message based on each output.
          const rl = readline.createInterface({
              input: proc.stdout
          });
          rl.on("line", (line) => {
              const payload = JSON.parse(line);
              this.send({
                  "topic": config.topic,
                  "payload": matrix(
                      parseInt(config.rows, 10),
                      parseInt(config.columns, 10),
                      payload.value.map(v => (v / MAG) - MAG))
              });
          });
  
          // Stop the server.
          this.on("close", (done) => {
              if (exited) {
                  done();
                  return;
              }
  
              // Wait the server is closed.
              proc.on("exit", () => {
                  done();
              });
  
              // Send a signal.
              this.log("DLPA server is closing");
              proc.stdin.close();
              rl.close();
              logger.close();
              proc.kill();
  
          });
  
      }
docs: DLPA Server Node.