public function delete($condition)
    {
        $result = null;
        $this->hook->attach('product.class.field.delete.before', $condition, $result, $this);

        if (isset($result)) {
            return (bool) $result;
        }

        if (!is_array($condition)) {
            $condition = array('product_class_field_id' => $condition);
        }

        $result = (bool) $this->db->delete('product_class_field', $condition);
        $this->hook->attach('product.class.field.delete.after', $condition, $result, $this);
        return (bool) $result;
    }