public static function get_slide_by_id($dataDir = null)
{
# Instantiate Presentation class that represents the presentation file
$pres = new Presentation($dataDir . 'Aspose.pptx');
# Getting Slide ID
$id = $pres->getSlides()->get_Item(0)->getSlideId();
# Accessing Slide by ID
$slide = $pres->getSlideById($id);
print "Slide: " . $slide . PHP_EOL;
}