package Base;

sub new {
   my ($class) = @_;
   return bless({}, $class);
}

sub method { print("Base.\n") }


package Child;

our @ISA = 'Base';

sub method { print("Child!\n") }


package main;

my $o;
$o = Base->new();
$o->method();
$o = Child->new();
$o->method();