Link Contacts PHP iSDK example

Hi, i was exploring IS API docs to find method of ‘Link Contacts’ and was unable to find example here https://developer.infusionsoft.com/docs/xml-rpc/#contact-link-contacts can anyone tell me is the following example code correct?

$contactId1 = 123;
$contactId2 = 456;
$linkTypeId = 789;
$result = $app->linkContacts($contactId1, $contactId2, $linkTypeId);

ok got the answer from How can I link contacts via the PHP ISDK? i added following public function in isdk.php and called the above example code and was succesfull:

public function linkContacts($contactId1, $contactId2, $contactLinkTypeId){
    $carray = array(
         php_xmlrpc_encode((int) $contactId1),
         php_xmlrpc_encode((int) $contactId2),
         php_xmlrpc_encode((int) $contactLinkTypeId)
    );
    return $this->methodCaller("ContactService.linkContacts", $carray);
}