TimePeriod::prepareTimePeriodForYear

private function prepareTimePeriodForYear($value)
{
	$year = $value['year'];
	$yearStartStr = $year . '01-01 00:00';
	$yearEndStr = $year + 1 . '01-01 00:00';
	$result = array(
		'start' => new DateTime($yearStartStr, 'Y-m-d H:i'),
		'end' => new DateTime($yearEndStr, 'Y-m-d H:i'),
	);
	return $result;
}