use strict;
use warnings;

package One;

sub MODIFY_CODE_ATTRIBUTES {
    my ( $pkg, $ref, @attr ) = @_;
    print "Package One handler given (@attr) and handles 'Eins'\n";
    return grep { $_ ne 'Eins' } @attr;
}

package Two;

use base qw(One);

sub MODIFY_CODE_ATTRIBUTES {
    my ( $pkg, $ref, @attr ) = @_;
    print "Package Two handler given (@attr) and handles 'Zwei'\n";
    return grep { $_ ne 'Zwei' } @attr;
}

package Three;

sub MODIFY_CODE_ATTRIBUTES {
    my ( $pkg, $ref, @attr ) = @_;
    print "Package Three handler given (@attr) and handles 'Drei'\n";
    return grep { $_ ne 'Drei' } @attr;
}

package Four;

sub empty {}

package Five;
use base qw[ Two Three Four ];
use Class::ISA;

sub MODIFY_CODE_ATTRIBUTES {
    my ( $pkg, $ref, @attr ) = @_;
    foreach my $class (Class::ISA::super_path($pkg)) {
        @attr = $class->MODIFY_CODE_ATTRIBUTES( $ref, @attr )
            if $class->can('MODIFY_CODE_ATTRIBUTES');
    }

    print "These attributes are left over (@attr) \n" if @attr;
    return @attr;
}

sub foo : Eins Zwei Drei {
}

__END__