Wonder if all my custom "merge" stuff can be safely overridden by https://hackage.haskell.org/package/containers-0.6.5.1/docs/Data-Map-Merge-Lazy.html#g:7
Wonder if all my custom "merge" stuff can be safely overridden by https://hackage.haskell.org/package/containers-0.6.5.1/docs/Data-Map-Merge-Lazy.html#g:7