package Invalid;

use base qw(HTML::Form);
use strict; # || loose(XP);

sub new {
  my $class = ref($_[0]) || $_[0]; shift;
  my $self = $class->SUPER::new(@_);
  return(bless($self,$class));
}

sub your_overwritten_routine {
  my $self = shift;
  ... and the rest of your code ...
  return $something;
}

"True value";