IsTrue example

$this->eventDispatcher->dispatch($event);

        $response->headers->set(PlatformRequest::HEADER_CONTEXT_TOKEN, $newToken);

        return $response;
    }

    private function getBeforeConfirmValidation(string $emHash): DataValidationDefinition
    {
        $definition = new DataValidationDefinition('registration.opt_in_before');
        $definition->add('em', new EqualTo(['value' => $emHash]));
        $definition->add('doubleOptInRegistration', new IsTrue());

        return $definition;
    }
}