I seem to be having confusion at the runRVar level of random-fu.

I can't figure out how to use the Data.Random.Source.PureMT module to get a meaningful random source (I can't get my code to type-check).

I wrote a [trivial] flipCoin function
> flipCoin = uniform False True
and am trying to fill in the final place of runRVar
> :t runRVar (replicateM 20 flipCoin)
runRVar (replicateM 20 flipCoin)
  :: (RandomSource m s) => s -> m [Bool]


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