Php, getInstanceByName

[gintare]

I am following the book "https://www.packtpub.co m/":
https://www.packtpub.co m/web-development/cms-design-using-php-and-jquery

On chapter one the give simple CMS example.

I am not able to understand the line:
$r=Page::getIns tanceByName($pa ge);

From where the method "getInstanceByN ame" is called?
I could not find such a method in the official Php documentation:
http://php.net/manual-lookup.php?patt ern=getInstance ByName&scope=qu ickref

<?php
//  index.php
// { common variables and functions
include_once('ww.incs/common.php');
$page=isset($_REQUEST['page'])?$_REQUEST['page']:'';
$id=isset($_REQUEST['id'])?(int)$_REQUEST['id']:0;

// }

// { get current page id
if(!$id){
	if($page){ // load by name
		$r=Page::getInstanceByName($page);
		if($r && isset($r->id))$id=$r->id;
	}
	if(!$id){ // else load by special
		$special=1;
		if(!$page){
			$r=Page::getInstanceBySpecial($special);
			if($r && isset($r->id))$id=$r->id;
		}
	}
}

The example code also throws error on windows Apache, but i am not dealing with them now. Please find CMS files enclosed.

[gintare]

I am sorry. Seems i become tired. The method "getInstanceByN ame" exists in the class:
C:\Bitnami\wamp stack-5.4.38-0\apache2\htdoc s\cms\ww.php_cl asses\Page.php