package Siberia::Indent {

    use Role::Tiny;

    requires qw(beer);

    sub back { ... }

    sub over { ... }

    1;

}

package Siberia::Acme {

    use Class::Tiny qw(beer); # whatever you need
    use Role::Tiny::With;

    with qw(Siberia::Indent);

    1;

}

#!/usr/bin/env perl

use strict;
use warnings;
use Siberia::Acme;
use Try::Tiny;
use feature qw(say);

my $indent = Siberia::Acme->new( { beer => 2 } );

# say $indent->beer;

try {
    $indent->back;
}
catch {
    say qq($_);
};

try {
    $indent->over;
}
catch {
    say qq($_);
};

__END__