/**
  * @param array[]|null $usages
  * @param string $timestamp
  *
  * @return ParserOutput
  */
 private function newParserOutput(array $usages = null, $timestamp)
 {
     $output = new ParserOutput();
     $output->setTimestamp($timestamp);
     if ($usages) {
         $acc = new ParserOutputUsageAccumulator($output);
         foreach ($usages as $u) {
             $acc->addUsage($u);
         }
     }
     return $output;
 }