function createPort(portId, opt_name) {
    if (ports[portId])
      throw new Error("Port '" + portId + "' already exists.");
    var port = new Port(portId, opt_name);
    ports[portId] = port;
    return port;
  }
// people add arbitrary port IDs to the port list.
people add arbitrary port IDs to the port list.
people add arbitrary port IDs to the port list .
function createPort(portId, opt_name) {
    if (ports[portId])
      throw new Error("Port '" + portId + "' already exists.");
    var port = new Port(portId, opt_name);
    ports[portId] = port;
    return port;
  }
function createPort ( portId , opt_name ) { if ( ports [ portId ] ) throw new Error ( "Port '" + portId + "' already exists." ) ; var port = new Port ( portId , opt_name ) ; ports [ portId ] = port ; return port ; }
people add arbitrary port IDs to the port list.
people add arbitrary port IDs to the port list .