INIT{ package TestClass;
...

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

my $obj=TestSubClass->new;

INIT{ package TestClass;
  sub new {
    my $class = shift;
    my $self = {};
    print "I'm brand new!\n";
    bless $self, $class;
  }
  1;
}

INIT{ package TestSubClass;
  use base "TestClass";
  1;
}