public static function purge_contact($contact_id)
 {
     $subscriber = EZP_CS_Subscriber_Entity::get_by_contact_id($contact_id);
     if ($subscriber != null) {
         $subscriber->delete();
     }
     $emails = EZP_Email_Entity::get_by_contact_id($contact_id);
     foreach ($email as $email) {
         /* @var $email EZP_Email_Entity */
         $email->delete();
     }
     EZP_Contact_Entity::delete_by_id($contact_id);
 }