public function getRespondentFields($requests)
    {
        $token   = $this->token;
        $results = [];

        $respondent = $token->getRespondent();

        foreach ($requests as $original => $upperField) {
            switch ($upperField) {
                case 'AGE':
                    $results[$original] = $respondent->getAge();
                    break;

                case 'SEX':
                    $results[$original] = $respondent->getGender();
                    break;

                case 'BIRTHDATE':
                    $birthDate = $respondent->getBirthday();
                    if (!is_null($birthDate) && $birthDate instanceof \MUtil_Date) {
                        $birthDate          = $birthDate->get('yyyy-MM-dd');
                        $results[$original] = $birthDate;
                    }
                    break;

                default:
                    break;
            }
        }

        return $results;
    }