code: private function _convertListFinancialEvents($request) {
  
          $parameters = array();
          $parameters['Action'] = 'ListFinancialEvents';
          if ($request->isSetSellerId()) {
              $parameters['SellerId'] =  $request->getSellerId();
          }
          if ($request->isSetMWSAuthToken()) {
              $parameters['MWSAuthToken'] =  $request->getMWSAuthToken();
          }
          if ($request->isSetMaxResultsPerPage()) {
              $parameters['MaxResultsPerPage'] =  $request->getMaxResultsPerPage();
          }
          if ($request->isSetAmazonOrderId()) {
              $parameters['AmazonOrderId'] =  $request->getAmazonOrderId();
          }
          if ($request->isSetFinancialEventGroupId()) {
              $parameters['FinancialEventGroupId'] =  $request->getFinancialEventGroupId();
          }
          if ($request->isSetPostedAfter()) {
              $parameters['PostedAfter'] =  $request->getPostedAfter();
          }
          if ($request->isSetPostedBefore()) {
              $parameters['PostedBefore'] =  $request->getPostedBefore();
          }
  
          return $parameters;
      }
docs: Convert ListFinancialEventsRequest to name value pairs