/**
* @param ErrorCollection $errors
* @param EncodingParametersInterface $parameters
*/
protected function checkFieldSets(ErrorCollection $errors, EncodingParametersInterface $parameters)
{
$withinAllowed = $this->isFieldsAllowed($parameters->getFieldSets());
$withinAllowed === true ?: $errors->addQueryParameterError(QP::PARAM_FIELDS, T::t('Field sets should contain only allowed ones.'));
}