public function get($name)
    {
        if (! $this->has($name)) {
            throw new Exception\HelperNotFoundException("Helper '$name' not found");
        }

        if (! isset($this->helpers[$name])) {
            $factory = $this->factories[$name];
            $this->helpers[$name] = $factory();
        }

        return $this->helpers[$name];
    }