git branch: multiple --merged and --no-merged options?

I find myself frequently running commands like this

  $ comm -12 <(git branch --no-merged master) <(git branch --merged next)

when checking for graduation candidates. Of course I first tried

  $ git branch --no-merged master --merged next

but this is equivalent to

  $ git branch --merged next


Isn't this query common enough to have a nicer interface? What do other
people use?