public function WorkflowGetProxyApprovalsByDelegatorId($delegator_id, $start, $end = false)
 {
     // $delegator_id : IDType (only one)
     // $start        : UNIX timestamp
     // $end          : UNIX timestamp (optional)
     $this->CheckAndSetHeader(__FUNCTION__);
     $reg_args["delegator_id"] = $delegator_id;
     $reg_args["start"] = gmdate(W3C_DATETIME_FORMAT, $start);
     if ($end !== false) {
         $reg_args["end"] = gmdate(W3C_DATETIME_FORMAT, $end);
     }
     $this->encodeString($reg_args);
     $results = parent::WorkflowGetProxyApprovalsByDelegatorId($reg_args);
     $this->methodClose();
     return $this->decodeString($results->application);
 }