LICENSE   := GPLv3
 VERSION   := git
 DOWNLOADS := numptyphysics.git

 URL(numptyphysics) := https://github.com/thp/numptyphysics.git
 DIR(numptyphysics) := src/app/numptyphysics
 REV(numptyphysics) := 336729c44c9ced3907d049cc1c1130a26c5708a3

hash file with following content：

dummy

when i   use prepare _port  tool:

<genode-dir>/tool/prepare_port numptyphysics CHECK_HASH=no
with following errors:
Error: Port numptyphysics lacks a valid hash
make: *** [nonexisting_hash] Error 1
why i use argument “CHECK_HASH=no”?but it still report the error.