Hello world PHP custom module

I have made a few node custom modules and now need to create php versions.

Can anybody see why this hello world module does not work?

    {
    type: 'custom',
    module : 'custom',
    action : 'order_submit',
    groupTitle : 'Custom Actions',
    groupIcon : 'fas fa-lg fa-database comp-data',
    title : 'Order Submit @@var(actionName)@@',
    icon : 'fas fa-lg fa-table comp-data',
    dataScheme: [
       {name: 'response', type: 'text'}
    ],
    dataPickObject: true,
    properties : [
        {
        group: 'Order Submit Properties',
        variables: [
            { name: 'actionName', optionName: 'name', title: 'Name', 
            type: 'text', required: true, defaultValue: ''},
            
            { name: 'output', optionName: 'output', title: 'Output', type: 'boolean', defaultValue: false }
        ]
        }
    ]
    }

<?php

namespace modules;

use \lib\core\Module;

class custom extends Module
{
  public function setvalue($options, $name) {

    $myObj->response = "Hello World";


    return json_encode($myObj);
  }
}

?>

{
  "code": 0,
  "file": "/opt/bitnami/apache/htdocs/dmxConnectLib/lib/App.php",
  "line": 197,
  "message": "Object of class modules\\custom could not be converted to string",
  "trace": "#0 /opt/bitnami/apache/htdocs/dmxConnectLib/lib/App.php(127): lib\\App->execSteps()\n#1 /opt/bitnami/apache/htdocs/dmxConnectLib/lib/App.php(94): lib\\App->exec()\n#2 /opt/bitnami/apache/htdocs/dmxConnect/api/abc.php(8): lib\\App->define()\n#3 {main}"
}

The error message seems to have an extra backslash – or is that just escaped???