function classExtends (context, parentConstructor, ...superArgs) {
  let parent = parentConstructor.call(context, ...superArgs)

  for(let key in parent) {
    let value = parent[key]

    if(typeof value == 'function') {
      context[key] = value.bind(context)
    } else {
      context[key] = value
    }
  }
}

global.classExtends = classExtends