private function parseDateFields()
    {
        if ('' === $this->getFromDate()) {
            $this->unsFromDate();
        }

        if ('' === $this->getToDate()) {
            $this->unsToDate();
        }

        foreach ([self::FROM_DATE, self::TO_DATE] as $dateField) {
            if ($this->hasData($dateField) && is_string($this->getData($dateField))) {
                $this->setData($dateField, $this->dateFilter->filter($this->getData($dateField)));
            }
        }
    }