TaskService::getTaskClosedDate

public function getTaskClosedDate($taskId)
{
	try
	{
		$taskItemObject = $this->getTaskItemObject($taskId);

		$taskData = $taskItemObject->getData(false, [
			'select' => [
				'CLOSED_DATE'
			]
		]);

		if ($taskData['CLOSED_DATE'])
		{
			return TypeDateTime::createFrom($taskData['CLOSED_DATE']);
		}
	}
	catch (Exception $exception)
	{
		$message = $exception->getMessage().$exception->getTraceAsString();

		$this->errorCollection->setError(
			new Error($message, self::ERROR_COULD_NOT_READ_TASK)
		);
	}

	return null;
}