def METHOD_NAME(self):
    val = self.dateTime()
    now = QtCore.QDateTime.currentDateTime()
    if self._block_past_date and val < now:
        logger.error('Selected date cannot be lower than current date.')
        return
    if self.relative:
        new_value = now.msecsTo(val)
    else:
        new_value = val.toMSecsSinceEpoch()
    if self.timeBase == TimeBase.Seconds:
        new_value /= 1000.0
    self.send_value_signal.emit(new_value)