Alaouy\Youtube\Youtube::getPlaylistsByChannelId PHP Method

    public function getPlaylistsByChannelId($channelId, $optionalParams = array(), $part = ['id', 'snippet', 'status'])
    {
        $API_URL = $this->getApi('playlists.list');
        $params = array('channelId' => $channelId, 'part' => implode(', ', $part));
        if ($optionalParams) {
            $params = array_merge($params, $optionalParams);
        }
        $apiData = $this->api_get($API_URL, $params);
        $result = ['results' => $this->decodeList($apiData)];
        $result['info']['nextPageToken'] = isset($this->page_info['nextPageToken']) ? $this->page_info['nextPageToken'] : false;
        $result['info']['prevPageToken'] = isset($this->page_info['prevPageToken']) ? $this->page_info['prevPageToken'] : false;
        return $result;
    }

 public function testGetPlaylistById()
 {
     //get one of the playlist
     $GOOGLE_CHANNELID = 'UCK8sQmJBp8GCxrOtXWBpyEA';
     $response = $this->youtube->getPlaylistsByChannelId($GOOGLE_CHANNELID);
     $playlist = $response[0];
     $response = $this->youtube->getPlaylistById($playlist->id);
     $this->assertEquals('youtube#playlist', $response->kind);
 }