gistfile1.txt

package MyRole;

...

package MyBaseThing;

with MyRole;

....


package MyConcreteThing1;

extends MyBaseThing;

...

package MyConcreteThing2;

extends MyConcreteThing1;

...

# then in your class ...

package MyApp;

has thing => (
    is => rw,
    does => MyRole,
    handles => MyRole,
);