如何将模板应用于Symfony2中的一个表单？

Page has two forms:

<div class="row">
  <div class="col-lg-6">
    {{ form(form) }}
  </div>
</div>
<div class="row">
  <div class="col-lg-6">
    {{ form(user) }}
  </div>
</div>

I set a theme for the form

{% form_theme form 'AcmeDemoBundle:Form:fields.html.twig' %}

But the theme is applied to both forms My theme

{% block form_row -%}
  <div class="form-group">
    {{- form_label(form) -}}
    {{- form_errors(form) -}}
    {{- form_widget(form, { 'attr' :{ 'class' : 'form-control' }}) -}}
  </div>
{%- endblock form_row %}

{% block button_row -%}
  {{- form_widget(form, { 'attr' : { 'class': 'btn btn-default' }}) -}}
{%- endblock button_row %}

But I need to theme applies only to form