{% macro render_submit() %}
<div class="control-group">
  <div class="controls">
    <input type="submit"
    {%- for key, value in kwargs.items() %}
      {{key}}="{{value}}"
    {% endfor %}
    />
  </div>
</div>
{%- endmacro %}

{% macro render_field(field) %}
<div class="control-group">
  {{ field.label }}
  <div class="controls">
    {{ field(**kwargs)|safe }}
    {{ render_errors(field.errors) }}
  </div>
</div>
{%- endmacro %}

{% macro render_csrf(form) %}
{{ form.csrf_token }}
{%- if 'csrf_token' in form.errors %}
<div class="control-group">
  <div class="controls">
    {{ render_errors(form.errors.csrf_token) }}
  </div>
</div>
{%- endif %}
{%- endmacro %}

{% macro render_errors(errors) %}
  {%- if errors|length == 1 %}
  <div class="errors">
    {{ errors.0 }}
  </div>
  {% elif errors %}
  <ul class="errors">
  {% for error in errors %}
    <li>{{ error }}</li>
  {% endfor %}
  </ul>
  {% endif %}
{%- endmacro %}