->add('quantity', IntegerType::class, [
                'required' => false,
                'empty_data' => '',
                'constraints' => [
                    new Assert\Regex([
                        'pattern' => "/^(\d+)?$/u",
                        'message' => 'form_error.numeric_only',
                    ]),
                    new Assert\Length(['max' => 11]),
                ],
            ])