Transformer/UnsetTransformer.php
public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setRequired('property');
        $resolver->setAllowedTypes('property', 'string');

        $this->configureWrappedConditionOptions('condition', $resolver);
    }
public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setRequired('property');
        $resolver->setAllowedTypes('property', 'string');

        $this->configureWrappedConditionOptions('condition', $resolver);
    }
{@inheritdoc}