/**
  * Method to return the total number of clicks and impressions
  * received by an agencies ads for hours inclusive of a given date range.
  *
  * see {@link Admin_DA::getAdsStatsByDate()} for date information
  *
  * @param integer $id agency id
  * @param object $oStart start of date range
  * @param object $oEnd end of date range
  * @return mixed array or PEAR::Error object
  */
 function getAgencyAdStats($id, $oStart, $oEnd)
 {
     // Validate args
     if (!empty($id) && is_a($oStart, 'Date') && is_a($oEnd, 'Date')) {
         if ($oEnd->after($oStart)) {
             $aAds =& Admin_DA::getAdsByAgencyId($id);
             if (PEAR::isError($aAds)) {
                 return $aAds;
             }
             return Admin_DA::getAdsStatsByDate($aAds, $oStart, $oEnd);
         } else {
             return MAX::raiseError("Invalid arguments passed to " . __CLASS__ . '::' . __FUNCTION__ . '
             end date is before or equal to start date.', MAX_ERROR_INVALIDARGS);
         }
     } else {
         return MAX::raiseError("Invalid arguments passed to " . __CLASS__ . '::' . __FUNCTION__, MAX_ERROR_INVALIDARGS);
     }
 }