Processing XCF files in batch

[Mate de Vita]

So this is how far I've gotten using the GIMP docs and a ton of googling:

I find my files in a python script and then use the following code to call a separate GIMP script on each of the files:

Code:

for f in found_files:
    scriptpath = r'path/to/script'
    scriptname = 'gimp.py'
    pycode = f'import sys; sys.path.insert(0, "{scriptpath}"); import {scriptname}; {scriptname}.run({f})'
    subprocess.run(f'gimp -idf --batch-interpreter python-fu-eval -b \'{pycode}\' -b \'pdb.gimp_quit(1)\'', shell=True, check=True)

The gimp.py file then contains the following code:

Code:

from gimpfu import *
import gimpcolor


def run(f):
   xcf = pdb.gimp_xcf_load(0, f, f)
   for layer in xcf.layers:
       layer.opacity = 100.
   if layer.name == 'Currently Green':
       pdb.gimp_context_set_foreground(gimpcolor.RGB(255, 0, 0))
       layer.fill(FOREGROUND_FILL)
   elif layer.name == 'Currently Red':
       pdb.gimp_context_set_foreground(gimpcolor.RGB(0, 255, 0))
       layer.fill(FOREGROUND_FILL)
   pdb.gimp_xcf_save(0, xcf, None, '/path/to/save/to.xcf', '/path/to/save/to.xcf')
   xcf.merge_visible_layers(NORMAL_MODE)
   pdb.file_png_save(xcf, xcf.layers[0], '/export/path.png', '/export/path.png', 0, 9, 1, 0, 0, 1, 1)

However this results in a bunch of batch command experienced an execution error error messages, which I don't know how to debug, since printing doesn't seem to work from the gimp script so I can't even tell where the error is happening.

What would be the correct way to fill the layers with the desired colours?