update meteredunit to have abstract methods
update meteredunit to have abstract methods


Former-commit-id: e2d0ff17524fbaf167540449ea98c1162c94fbfe
Former-commit-id: a78d0285ae92aa16c8f5f66ce64175e3e18d3f1a
dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy