going in
in new for cChild and just calling sub_passed_to_child
yes in passed_sub
$oParent_ref is cParent=HASH(0xf18038)
$oParent_ref->{test_att} is 3

##</code><code>##

     ##OLD  $self->{sub_passed_to_child}( $self->{parent_obj_ref} );
          $self->{sub_passed_to_child}->( $self ); ##New, explicitly de-ref the sub

##</code><code>##

   sub passed_sub {
    print "yes in passed_sub\n";
    my ($child) = @_; # I don't like using shift here..
    print $child->{parent_obj_ref}{test_att}; # 3