SubmitTypeValidatorExtension example

public function loadTypeGuesser(): ?FormTypeGuesserInterface
    {
        return new ValidatorTypeGuesser($this->validator);
    }

    protected function loadTypeExtensions(): array
    {
        return [
            new Type\FormTypeValidatorExtension($this->validator, $this->legacyErrorMessages, $this->formRenderer, $this->translator),
            new Type\RepeatedTypeValidatorExtension(),
            new Type\SubmitTypeValidatorExtension(),
        ];
    }
}