{% macro render_field(field) %}
<div class="form-group row mb-3">
  {{ field.label(class_="col-form-label col-sm-3 text-right") }}
  {% if field.errors %}{% set class_extras = " is-invalid" %}{% else %}{% set class_extras = "" %}{% endif %}
  <div class="col-sm-5">{{ field(class_="form-control" + class_extras) }}
  {% if field.errors %}
  <div class="invalid-feedback">
  {% for error in field.errors %}
    {{ error }}
  {% endfor %}
  </div>
  {% endif %}
</div></div>
{%- endmacro %}

{% macro render_button(button) %}
<div class="form-group row"><div class="offset-sm-3 col-sm-5">{{ button(class_="btn btn-primary") }}</div></div>
{%- endmacro %}