[FragileTitanium]

Hello, don't know if this is the correct place to post this issue. Hope you will forgive me if it isn't.
I'm trying to convert a KPF file (wrapped PDF) to a KFX file using KFX Output CLI, to be sideloaded on my Kindle Scribe as a writable PDF. I opened command prompt and went to the directory where the KPF file is, and copy-pasted instructions by jhowell's found in this forum. So i pasted this on command prompt: calibre-debug -r "KFX Output" -- "filename.kpf". (filename obviously sobsitutes the name of the file for privacy). Then I get a syntax error:

>>> calibre-debug -r "KFX Output" -- "filename.kpf"
File "<console>", line 1
calibre-debug -r "KFX Output" -- "filename.kpf"
^^^^^^^^^^^^
SyntaxError: invalid syntax

All plugins are correctly installed in Calibre and work well in the software.