public function retrieve()
    {
        $messages = null;

        if (\is_null($this->instance)) {
            $this->instance = new static();
            $this->instance->setSessionStore($this->session);

            if ($this->session->has('message')) {
                $messages = \unserialize($this->session->pull('message'), ['allowed_classes' => false]);
            }

            if (\is_array($messages)) {
                $this->instance->merge($messages);
            }
        }

        return $this->instance;
    }