code: protected function loadRequestCreator($requestCreator, $params, $libIdentifier, $originatorOffice, $mesVer)
      {
          if ($requestCreator instanceof RequestCreatorInterface) {
              $newRequestCreator = $requestCreator;
          } else {
              $params->originatorOfficeId = $originatorOffice;
              $params->messagesAndVersions = $mesVer;
  
              $newRequestCreator = RequestCreatorFactory::createRequestCreator(
                  $params,
                  $libIdentifier
              );
          }
  
          return $newRequestCreator;
      }
docs: Load a request creator
  
  A request creator is responsible for generating the correct request to send.
  
  @param RequestCreatorInterface|null $requestCreator
  @param Params\RequestCreatorParams $params
  @param string $libIdentifier Library identifier & version string (for Received From)
  @param string $originatorOffice The Office we are signed in with.
  @param array $mesVer Messages & Versions array of active messages in the WSDL
  @return RequestCreatorInterface
  @throws \RuntimeException