JSFiddle - React, Tailwind, and code Playground

HTML

<p>
    Решение задачи не принимает мотивируя :
<br>
should not overwrite existing objects in the namespace
    Value is not what was expected <br>
should not replace the existing namespace object
    Value is not what was expected</p>

JavaScript

var MyNamespace = {
  MyClass : function(param) {
    this.param = param;
  }
}
MyNamespace.MyClass.prototype.sayHello  = function(param) {
      return this.param; 
 }
var myObject = new MyNamespace.MyClass('Hello');
var phrase = myObject.sayHello();