code: private function _convertListFinancialEventsByNextToken($request) {
  
          $parameters = array();
          $parameters['Action'] = 'ListFinancialEventsByNextToken';
          if ($request->isSetSellerId()) {
              $parameters['SellerId'] =  $request->getSellerId();
          }
          if ($request->isSetMWSAuthToken()) {
              $parameters['MWSAuthToken'] =  $request->getMWSAuthToken();
          }
          if ($request->isSetNextToken()) {
              $parameters['NextToken'] =  $request->getNextToken();
          }
  
          return $parameters;
      }
docs: Convert ListFinancialEventsByNextTokenRequest to name value pairs