EDIT

<?php

class AgentComposeHandler extends ItemComposeHandler {

  private $enclosing_tag = 'div';

  public function getClassAttributes($item) {

    return $this->classAttributes($item);

  }

  public function composeItem($item) {

    return compose_agent($item, $this->enclosing_tag);

  }

}

<?php

abstract class ItemComposeHandler {

  abstract public function getClassAttributes($item);

  abstract public function composeItem($item);

  /**

   * @param $cdm_entity

   * A CDM native entity. In case of DTOs the cdm entity can be substituted by

   * TypedEntityReference

   *

   * @return string

   */

  protected function classAttributes($cdm_entity) {

    return html_class_attribute_ref($cdm_entity);

  }

}

<?php

class RegistrationDTOComposeHandler extends ItemComposeHandler {

  public function getClassAttributes($item) {

    return $this->classAttributes(new TypedEntityReference("Registration", $item->uuid));

  }

  public function composeItem($item) {

    return compose_registration_dto_compact($item, 'item-style', 'div');

  }

}

<?php

/**

 * Compose a description as a table of Feature<->State

 *

 * @param $description_uuid

 *

 * @return array

 *    The drupal render array for the page

 *

 * @ingroup compose

 */

function compose_agent($agent, $enclosing_tag) {

  $name_details = [];

  if($agent->familyName){

    $name_details[] = '<span class="label">' . t('Family name') . ': </span>'. $agent->familyName;

  }

  if($agent->givenName){

    $name_details[] = '<span class="label">' . t('Given name') . ': </span>'. $agent->givenName;

  }

  $details[] = join(', ', $name_details);

  if($details[0]) {

    $details[0] = ' (' . $details[0] . ')';

  }

  if($agent->lifespan){

    // as first element after the titleCache

    $lifespan_text = timePeriodToString($agent->lifespan);

    if($lifespan_text){

      array_unshift($details, ", " . $lifespan_text);

    }

  }

  // FIXME:-------------------------------

  // 7d1a269b-9bdd-44eb-beba-2f8acee941af is the phycobank specific ext type for "Life span" which will become obsolte!!!!

  if(isset($visible_extensions_sorted['7d1a269b-9bdd-44eb-beba-2f8acee941af'])){

    // as first element after the titleCache

    array_unshift($details, ", " . $visible_extensions_sorted['7d1a269b-9bdd-44eb-beba-2f8acee941af'][0]->value);

    unset($visible_extensions_sorted['7d1a269b-9bdd-44eb-beba-2f8acee941af']);

  }

  // ------------------------------------

  // extensions

  $visible_extensions_sorted = visible_extensions_sorted($agent);

  $extensions = [];

  foreach ($visible_extensions_sorted as $type_uuid => $exts){

    foreach ($exts as $ext){

      if($ext->value){

        $extensions[] = '<span class="label">' . $ext->type->representation_L10n . ': </span>'. $ext->value;

      }

    }

  }

  $extensions_markup = join(', ', $extensions);

  if($extensions_markup){

    $details[] = $extensions_markup;

  }

  // IDs as last

  if(isset($agent->orcid)){

    $corcid_id = number_format($agent->orcid->digitsOnly, 0, '.', '-');

    $details[] = l('https://orcid.org/' . $corcid_id, 'https://orcid.org/' . $corcid_id);

  }

  if($agent->identifiers){

    $identifiers_render_array = compose_identifiers($agent->identifiers);

    $details[] = drupal_render($identifiers_render_array);

  }

  $details_markup = join(' ', $details);

  $render_array = markup_to_render_array($agent->titleCache . $details_markup, null, '<' . $enclosing_tag . ' class="' . html_class_attribute_ref($agent) . '">', '</' . $enclosing_tag . '>');

  return $render_array;

}