{--------------------------------------------------------------------
  Debugging
--------------------------------------------------------------------}
-- | /O(n)/. Show the tree that implements the set. The tree is shown
-- in a compressed, hanging format.
showTree :: Show a => Set a -> String
showTree s
  = showTreeWith True False s
showTree :: Show a => Set a -> String
showTree s
  = showTreeWith True False s
showTree s
  = showTreeWith True False s