public function newModel($modelName, $mixed = null) {
    if(substr_count("\\", $modelName) > 0) {
      throw new InvalidArgumentException("Do not provide the full namespace plus classname of the desired model.  Only the model classname is required.  E.G. Cloud");
    }

    $prefix = $this->version == '1.0' ? 'Ec2\\' : 'Mc\\';

    $modelName = "\\RGeyer\\Guzzle\\Rs\\Model\\" . $prefix . $modelName;

    if(!class_exists($modelName)) {
      throw new \InvalidArgumentException("The model $modelName does not exist");
    }

    $model = new $modelName($mixed);
    $model->setClient($this);

    return $model;
  }