/**
  * データベースに保存に設定されているフォーム(投稿)を取得
  *
  * @return array
  */
 public static function get_posts()
 {
     if (self::$contact_data_post_types !== null) {
         return self::$contact_data_post_types;
     }
     $contact_data_post_types = array();
     $Admin = new MW_WP_Form_Admin();
     $forms = $Admin->get_forms_using_database();
     foreach ($forms as $form) {
         $post_type = MWF_Functions::get_contact_data_post_type_from_form_id($form->ID);
         $contact_data_post_types[] = $post_type;
     }
     $raw_post_types = $contact_data_post_types;
     $new_post_types = array();
     $contact_data_post_types = apply_filters('mwform_contact_data_post_types', $contact_data_post_types);
     // もともとの配列に含まれていない値は削除する
     foreach ($contact_data_post_types as $post_type) {
         if (in_array($post_type, $raw_post_types)) {
             $new_post_types[] = $post_type;
         }
     }
     self::$contact_data_post_types = $new_post_types;
     return self::$contact_data_post_types;
 }