/**
  * This returns all models sorted by Make Title, then Model Title
  *
  * @return \SquirrelsInventory\Model[]
  */
 public static function getAllModels()
 {
     $models = array();
     $makes = Make::getAllMakes();
     $parents = array(0 => array());
     foreach ($makes as $make_id => $make) {
         $parents[$make_id] = array();
     }
     $query = new \WP_Query(array('post_type' => self::CUSTOM_POST_TYPE, 'post_status' => 'publish', 'posts_per_page' => -1, 'orderby' => 'title', 'order' => 'ASC'));
     if ($query->have_posts()) {
         while ($query->have_posts()) {
             $query->the_post();
             $custom = get_post_custom(get_the_ID());
             $model = new Model(get_the_ID(), get_the_title());
             if (array_key_exists('make_id', $custom)) {
                 $make_id = $custom['make_id'][0];
                 $model->setMakeId($make_id);
                 if (array_key_exists($model->getMakeId(), $makes)) {
                     $model->setMake($makes[$model->getMakeId()]);
                 }
             } else {
                 $make_id = 0;
             }
             $parents[$make_id][] = $model;
         }
     }
     foreach ($parents as $parent_id => $_models) {
         /** @var Model[] $_models */
         foreach ($_models as $model) {
             $models[$model->getId()] = $model;
         }
     }
     return $models;
 }