Temporary workaround function to flatten an IO of Either

utils.kt

class IOException(val error: Any?) : Exception()

/**
 * Flattens this IO's Either into IO itself, wrapping the untyped-Left side on a custom exception.
 * 
 * Note: This is a workaround until IO<E, A> is available
 */
fun <A, B> IO<Either<A, B>>.flattenEither(): IO<B> =
  this.flatMap {
    it.fold(ifLeft = {
      IO.raiseError<B>(IOException(it))
    }, ifRight = {
      IO.just(it)
    })
  }