__PACKAGE__->define_attributes(qw/
    foo
    bar
/);

##</code><code>##

sub import
{
    my $caller = (caller)[0];

    no strict 'refs';

   *{"${caller}::define_attributes"} = \&define_attributes;
   *{"${caller}::import"} = \&import;
}

##</code><code>##

{
    no strict 'refs';
    my $i = 0;
    while(my $caller = (caller($i))[0]) {
        unless ($caller eq 'main' or $caller eq 'base') {
            *{"${caller}::define_attributes"} = \&define_attributes;
        }
        $i++;
    }
}