src/Action/Conversation.php
public function add($message)
    {
        if (is_string($message)) {
            $this->messages[] = new SimpleResponse($message);
        } elseif ($message instanceof ResponseInterface) {
            $this->messages[] = $message;
        } elseif ($message instanceof QuestionInterface) {
            $this->messages[] = $message;
        }

        return $this;
    }
public function add($message)
    {
        if (is_string($message)) {
            $this->messages[] = new SimpleResponse($message);
        } elseif ($message instanceof ResponseInterface) {
            $this->messages[] = $message;
        } elseif ($message instanceof QuestionInterface) {
            $this->messages[] = $message;
        }

        return $this;
    }
Add a message.

@param string|Dialogflow\Action\Interfaces\ResponseInterface|Dialogflow\Action\Interfaces\QuestionInterface $message

@return Conversation