Calling a Python subroutine

I am trying to find out how to call a python subroutine with an o-call. Following the documentation,
the TOPLEVEL location is defined in the .ini file and the log shows that __INIT__ procedure is executed.

But the o<test1> call does not find the Python routine (test1.py) in /linuxcnc/ncfiles. The document says the
routine is called when an O-word call like o<proc> call is executed and the name oword.proc is defined and callable.

I could not find an example, but I assume the oword.proc module is a file with that name, with the Python routine inside.
Or is the name oword.test1 (in my case) defined somewhere else?

Thanks for any advice.

I don't think you can call a python program with an o call.

G-code remapping can call an o-sub or python. but that isn't the same thing.
You can run a python script file as a custom M-code. (M100...)

Yes,, of course. Sorry about using the wrong term. I write python subroutines in this case, essentially converting a lot of (somewhat incompatible) G-code routines that I wrote in the past. Picking up variables is well documented, but I am puzzled about where and how to define the oword module. I assume It can contain multiple subroutine definitions.

I am not looking at remapping existing code, but calling python subroutines from the main G-code.

Andy, are you sure your not confused? The links to the docs on o-code calls only seem to reference calling g-code subs. And for M100 codes, I thought for sure I had tried in the past to use a g-code sub as a custom M-code and failed, then asked about it and was told it wasn't possible,