ES6 Class is not a function when imported via System

System.Object 
  System.MarshalByRefObject
    System.ComponentModel.Component
      System.Windows.Forms.Control
          {your control here}

class C:
    def function6(self):
        print ("Hello")
    def function7(self):
        print ("Trudy")
 def sayHello():
    C().function6()
 def sayWorld():
    C().function7()

import test1
def function2():
    print ("World")

test1.C().function6()
function2()

const nodeModule = require('./nodeModule');
const sinon = require('sinon');

describe('ChildClass test', () => {

  describe('Sinon spy', () => {

    it('should call nodeModule.nodeModuleFunction with given value', done => {

      const spy = sinon.spy(nodeModule, 'nodeModuleFunction');  // create the spy...
      const ChildClass = require('./ChildClass');  // ...and now require ChildClass

      const object = new ChildClass();

      expect(object.message).not.toBeNull();  // Success!
      expect(spy.called).toBe(true);  // Success!
      expect(spy.withArgs('Some input').calledOnce).toBe(true);  // Success!

      object.message.then(message => {
        expect(message).toBe('Returned from node module.');  // Success!
        done();
      });
    });

  });

});