-import Bit as B (Bit(..))
-import Maskable (Maskable(..))
-import Maskbits (Maskbits(..))
+import Bit as B( Bit( Zero, One) )
+import Maskable( Maskable( apply_mask) )
+import Maskbits(
+ Maskbits( Zero, One, Two, Three, Four, Five, Six, Seven, Eight ) )