isBaseOf

$boolean = $session->isBaseOf( $class1, $class2 )

The isBaseOf() function returns TRUE if $class2 is a base class of $class1, that is, $class1 is derived from $class2.

Note:

For the purposes of this query, all classes are taken to be derived from themselves.

 $class1 = "Router";
 $class2 = "ICIM_UnitaryComputerSystem";
 $is_it = $session->isBaseOf( $class1, $class2 );