Symfony2 FOSUserBundle显示在树枝模板中过期

我想在我的树枝上显示expiresAt，但是出现此错误:

I want to display the expiresAt in my twig but i have this error :

 Method "expiresat" for object "AuthenticationBundle\Entity\User" does not exist in AdminNCBundle:NC:list_clients.html.twig at line 43 

在我的树枝上，我做了:

in my twig i have done a for :

   {% for client in clients %}
        <tr>
            <td>{{ client.firstname }} {{ client.lastname }}</td>
            <td>{{ client.telephone }}</td>
            <td>{{ client.registrationdate|date('Y-m-d H:i:s') }}</td>
            <td>{{ client.expiresat|date('Y-m-d H:i:s') }}</td>
            <td>{{ client.duration }}</td>
        </tr>
   {% endfor %}

注册日期显示得很好.