Base::prepareItemForGroupingByDate

private function prepareItemForGroupingByDate($array)
{
	/** @var DateTime|Date $date */
	$date = $array['DATE'];
	if ($date instanceof DateTime)
	{
		if(CTimeZone::Enabled())
		{
			$formatDate = $date->toUserTime()->format('Y-m-d H:i');
		}
		else
		{
			$formatDate = $date->format('Y-m-d H:i');
		}
	}
	else
	{
		$formatDate = $date->format('Y-m-d H:i');
	}
	return array(
		$formatDate => array(
		'label' => $formatDate,
		'value' => (int)$array['VALUE']
	));
}