$session->delete( $object );
The delete() function deletes the specified object instance from the repository.
Note:
This does not clean up all the object interdependencies and links. For a cleaner object deletion, use the remove() operation, if one exists, for the object class in question. The section “invoke” on page 98 also provides additional information to the related invoke() primitive.
The delete() method can be called in one of two ways.
$session->delete( $object );
or
$object->delete();