'custom_column_' ~ c.id]|length > 0 %}
                    value="{% if book['custom_column_' ~ c.id][0].value %}{{book['custom_column_' ~ c.id][0].value|formatdate}}{% endif %}"
                  {% endif %}>
                <span class="input-group-btn">
                  <button type="button" id="{{ 'custom_column_' ~ c.id }}_delete" class="datepicker_delete btn btn-default"><span class="glyphicon glyphicon-remove-circle"></span></button>
                </span>
              </div>
            {% endif 