public function resetReviews($from = null, $to = null)
    {
        $conn = $this->getConnection();
        if ($from && $to) {
            $where = [
                'created_at >= ?' => $from . ' 00:00:00',
                'created_at <= ?' => $to . ' 23:59:59',
                'review_imported is ?' => new \Zend_Db_Expr('not null')
            ];
        } else {
            $where = $conn->quoteInto(
                'review_imported is ?',
                new \Zend_Db_Expr('not null')
            );
        }
        $num = $conn->update(
            $this->getTable(Schema::EMAIL_REVIEW_TABLE),
            ['review_imported' => new \Zend_Db_Expr('null')],
            $where
        );

        return $num;
    }