public function getLastVideosFromUser($user_name, $count = 100)
  {
    $contentDetails = $this->query('channels', array(
      'part' => 'contentDetails',
      'forUsername' => $user_name,
    ));
    if($contentDetails) {
      $playlistId = $contentDetails['items'][0]['contentDetails']['relatedPlaylists']['uploads'];
      return $this->query('playlistItems', array(
        'part' => 'snippet',
        'playlistId' => $playlistId,
        'count' => $count
      ));
    }
    return null;
  }