function send_dm_by_name($screen_name, $text, $id = NULL)
{
$params = array();
$params['text'] = $text;
$params['screen_name'] = $screen_name;
if ($id) {
$this->id_format($id);
$params['id'] = $id;
}
return $this->oauth->post('direct_messages/new', $params);
}