Revert "add accumulate test"

This reverts commit 181cb78e6fd1e164bc44a7a7dec38ad06ff574bd.
Revert "@expand.valify"

This reverts commit d8118f877327f99613af66c69db03724db665f07.
Revert "accumulate.scala"

This reverts commit 342831b8c1c0d8a2cefda37fb8133b398e737e81.