coAxiomSingleBranch_maybe :: CoAxiom br -> Maybe CoAxBranch
coAxiomSingleBranch_maybe (CoAxiom { co_ax_branches = MkBranches arr })
  | snd (bounds arr) == 0
  = Just $ arr ! 0
  | otherwise
  = Nothing
coAxiomSingleBranch_maybe :: CoAxiom br -> Maybe CoAxBranch
coAxiomSingleBranch_maybe (CoAxiom { co_ax_branches = MkBranches arr })
  | snd (bounds arr) == 0
  = Just $ arr ! 0
  | otherwise
  = Nothing
coAxiomSingleBranch_maybe (CoAxiom { co_ax_branches = MkBranches arr })
  | snd (bounds arr) == 0
  = Just $ arr ! 0
  | otherwise
  = Nothing