public function getMediaUrl($mediaType)
    {
        $url = $this->body;

        if (is_array($this->body) && isset($this->body['attachment']['payload']['url']) && is_string($this->body['attachment']['payload']['url'])) {
            $url = $this->body['attachment']['payload']['url'];
        }

        $url = str_replace($mediaType . ':', '', $url);

        return $url;
    }