package Foo::Bar;

my @lineage = ('Mom', 'Dad');
@ISA = (@lineage);

sub selfcheck {
  die "You can\'t change who I am." unless __PACKAGE__ eq 'Foo::Bar';
  map {
    die "You can\'t change who my parents are." unless $lineage[$_] eq $ISA[$_]
  } (0..(scalar @ISA - 1));
}

sub DESTROY {
  $self->Foo::Bar::selfcheck;
}

sub method_name {
  my $self=shift;
  $self->Foo::Bar::selfcheck;

 # method stuff here
}

sub method_name2 {
  $self->Foo::Bar::selfcheck;
  # method stuff here
}