function fetchMargins($campaign_id, $start_date)
{
$method = 'campaigns/' . $campaign_id . '/margins.csv?start=' . date('Y-m-d', strtotime($start_date));
$response = array();
$response = parent::call($method, array());
$ret = array();
$ret = parent::csvArray($response['status']);
return $ret;
}
