{% if form.vars.choices|length == 1 %}
    <div class="col-lg-12 form-group">
        <label class="sr-only">{{form.vars.label}}</label>
        {{ form_widget(form, {'attr' : {'class' : 'form-control', 'placeholder' : form.vars.label}}|merge({'value': form.vars.choices[0].value})) }}
    </div>
{% else %}
    <div class="col-lg-12 form-group">
        <label class="sr-only">{{form.vars.label}}</label>
        {{ form_widget(form, {'attr' : {'class' : 'form-control', 'placeholder' : form.vars.label}}) }}
    </div>
{% endif %}