code: private function getOperationTypeNode($type, $operation)
      {
          $astNode = $this->schema->getAstNode();
  
          $operationTypeNode = null;
          if ($astNode instanceof SchemaDefinitionNode) {
              $operationTypeNode = null;
  
              foreach ($astNode->operationTypes as $operationType) {
                  if ($operationType->operation === $operation) {
                      $operationTypeNode = $operationType;
                      break;
                  }
              }
          }
  
          return $operationTypeNode ? $operationTypeNode->type : ($type ? $type->astNode : null);
      }
docs: @param Type   $type
  @param string $operation
  
  @return TypeNode|TypeDefinitionNode