prop_gen_intervals1 :: VersionIntervals' -> Bool
prop_gen_intervals1 (VersionIntervals' intervals) =
  isJust (mkVersionIntervals intervals)
prop_gen_intervals1 :: VersionIntervals' -> Bool
prop_gen_intervals1 (VersionIntervals' intervals) =
  isJust (mkVersionIntervals intervals)
prop_gen_intervals1 (VersionIntervals' intervals) =
  isJust (mkVersionIntervals intervals)