public function getRenderLabel($field_key, $required_mark = ' <span class="required">*</span>')
    {
        return sprintf(
            '<label for="%s">%s%s</label>',
            $field_key,
            $this->getLabelText($field_key),
            ($required_mark && $this->isRequired($field_key)) ? $required_mark : null
        );
    }