use warnings;
use strict;

package One;
require Exporter; # added
our @ISA =qw/Exporter/;# added
our @EXPORT = qw/foo/;# added

sub foo {
    print "I'm One::foo >> @_ \n"; # changed
}

package Two;

use base 'One';

sub new {
    return bless {}, shift;
}
sub foo {
    my $self = shift;

    print "I'm Two::foo(). I'm going to call " .
          "my Parent's foo()...\n";

    $self->SUPER::foo();
}

package main;

my $obj = Two->new;

$obj->foo("abc"); # Now foo() has an extra first element in @_
foo("abc"); # die() for Bareword from 'strict subs'


##</code><code>##

package Two;

use base 'One';
require Exporter;
our @EXPORT = qw/foo/;

*foo = \&One::foo;

sub new { ... }
sub newMethod { ... }
sub overrideOldMethod { ... }