public function buildChannel($channel, $max = 3, $refreshes = 'no')
    {
        $channels = $this->validateChannel($channel);

        $url = $this->getURL('channel');

        $headers = [
            'body' => [
                'private'   => $this->privateKey,
                'channel'   => $channels,
                'max'       => $max,
                'refreshes' => $refreshes
            ]
        ];

        $response = $this->processRequest($url, $headers, 'post');

        return $response;
    }