package Foo::BarMod;
 use Foo::Bar;
 @ISA = qw(Foo::Bar);
 sub stuff {
   my $self = shift;
   # Do stuff, overriding Foo::Bar::stuff
 }
 # Everything else, including new(), from Foo::Bar
 1;

##</code><code>##

  Undefined subroutine Foo::BarMod::whiz at line 17.

##</code><code>##

  # call class method whiz()
  Foo::BarMod::whiz();

##</code><code>##

  Foo::BarMod->whiz();
  whiz Foo::BarMod;

##</code><code>##

  Foo:BarMod::whiz;