code: public function executePsrRequest(ServerRequestInterface $request)
      {
          $parsedBody = $this->helper->parsePsrRequest($request);
  
          return $this->executeRequest($parsedBody);
      }
docs: Executes GraphQL operation and returns execution result
  (or promise when promise adapter is different from SyncPromiseAdapter)
  
  @return ExecutionResult|ExecutionResult[]|Promise
  
  @api