combineMap :: SourceMap -> InstalledMap -> CombinedMap
combineMap = Map.mergeWithKey
    (\_ s i -> Just $ combineSourceInstalled s i)
    (fmap PIOnlySource)
    (fmap (uncurry PIOnlyInstalled))
combineMap :: SourceMap -> InstalledMap -> CombinedMap
combineMap = Map.mergeWithKey
    (\_ s i -> Just $ combineSourceInstalled s i)
    (fmap PIOnlySource)
    (fmap (uncurry PIOnlyInstalled))
combineMap = Map.mergeWithKey
    (\_ s i -> Just $ combineSourceInstalled s i)
    (fmap PIOnlySource)
    (fmap (uncurry PIOnlyInstalled))