Digital B&W Conversion (GIMP)

I’m having a problem with pseudogrey. It generates the following error

Execution error for ‘Pseudogrey’:
Error: eval: unbound variable: NORMAL

Gimp 2.10.12

I find it very useful for some B&W conversions and will feel a bit lost without it. Hopping some one can sort. Tried the version of Pat David’s site. Seems to be the only copy around.

John