public function profileGetTaxonomyFieldValue($field_name, ProfileInterface $user_profile = NULL) {
    if ($user_profile === NULL) {
      return '';
    }

    $names = array_map(
      function (TermInterface $taxonomy_term) {
        return $taxonomy_term->getName();
      },
      $user_profile->get($field_name)->referencedEntities()
    );

    return implode(', ', $names);
  }