Base::prepareItemForGroupingByLine

private function prepareItemForGroupingByLine($array)
{
	$openLinesLabelMap = $this->getOpenLineLabelMap();
	return array(
		$array['OPEN_LINE_ID'] => array(
			'label' => isset($openLinesLabelMap[$array['OPEN_LINE_ID']]) ? $openLinesLabelMap[$array['OPEN_LINE_ID']] : 'Undefined',
			'value' => (int)$array['VALUE']
		));
}