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 ? $type->astNode : null);
    }
private function getOperationTypeNode($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);
    }
@param Type   $type
@param string $operation

@return TypeNode|TypeDefinitionNode