Usage

    VerticalDateRangePicker(
          firstDate: DateTime.now(),
          lastDate: DateTime(DateTime.now().year + 10),
          highLightColor: Colors.redAccent,
          onEndDateChanged: (date) {},
          selectedColor: Colors.redAccent,
          onStartDateChanged: (date) {},
          splashColor: Colors.redAccent,
          presentDayStrokeColor: Colors.black,
          selectedTextStyle: const TextStyle(
            fontWeight: FontWeight.bold,
            color: Colors.white,
          ),
          dayTextStyle: const TextStyle(
            color: Colors.black,
          ),
          initialDateRange: DateTimeRange(
            start: DateTime.now(),
            end: DateTime.now().add(
              const Duration(days: 3),
            ),
          ),
        );