function __construct($unit = 'day', $from = '-1 month', $to = 'now')
 {
     $this->timeUnits = TimeUnits::getInstance();
     $this->dataTable = new \NadeoLib\Google\Visualization\DataTable();
     $this->emptyData = $this->timeUnits->getTimeUnits2($unit, $from, $to);
 }