如何在beego模板循环中解析i18n字段？

If I use i18n statement in range statement, I got a template Execute err. But I move the i18n statement outside the range statement. It's OK. The error message is:

 [D] [controller.go:283]  template Execute err: template: userscontroller/get.tpl:16:244: executing "userscontroller/get.tpl" at <.Lang>: can't evaluate field Lang in type models.Account
[E] [server.go:2694]  template: userscontroller/get.tpl:16:244: executing "userscontroller/get.tpl" at <.Lang>: can't evaluate field Lang in type models.Account

This is my sample code:

<ul class="w3-ul" id="UserList">
        {{range $index, $user := .Users}}

        <li class="w3-bar w3-hover-light-blue {{if eq $user.Role  1}}w3-pale-green{{end}} {{if eq $user.Role  2}}w3-pale-blue{{end}}{{if eq $user.Role  3}}w3-pale-red{{end}}" onclick="openProfile(this,{{$user.Uid}})">

          <div class="w3-bar-item">
            {{if eq $user.Role  1}}<span class="w3-large" style="color:green;    font-weight: bold;">{{i18n .Lang ".users.administrator"}}</span>{{end}}{{if eq $user.Role  2}}<span class="w3-large" style="color:blue;    font-weight: bold;">{{i18n .Lang ".users.user"}}</span>{{end}}{{if eq $user.Role  3}}<span class="w3-large" style="color:red;    font-weight: bold;">{{i18n .Lang ".users.inactivated"}}</span>{{end}}<span class="w3-large Last">{{$user.Last}}</span> <span class="w3-large First">{{$user.First}}</span><br>
            <span>{{i18n .Lang ".users.email"}}</span><span class="Email">{{$user.Email}}</span>
          </div>
        </li>
        {{end}}


    </ul>

Has anyone encountered a similar problem? How to solve it, thank you.