prettyPreAcc pp alvl wrap (Fold1Seg f acc1 acc2)
  = wrap 
  $ prettyArrOp "fold1Seg" [parens (prettyPreFun pp alvl f), pp alvl parens acc1,
                            pp alvl parens acc2]
prettyPreAcc pp alvl wrap (Fold1Seg f acc1 acc2)
  = wrap 
  $ prettyArrOp "fold1Seg" [parens (prettyPreFun pp alvl f), pp alvl parens acc1,
                            pp alvl parens acc2]
prettyPreAcc pp alvl wrap (Fold1Seg f acc1 acc2)
  = wrap 
  $ prettyArrOp "fold1Seg" [parens (prettyPreFun pp alvl f), pp alvl parens acc1,
                            pp alvl parens acc2]