Namibia ['NA'] not accepted as string in save_osm_data

[LRydin]

Describe the bug
Rather straightforward. ['NA'] not accepted as string. save_osm_data gets nowhere

To Reproduce

from earth-osm import eo
eo.save_osm_data(['NA'], 'power', ['substation'])

results in an error

ERROR:eo.gfk:NA not found. Check eo.view_regions() or run 'earth_osm view regions'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ubuntu/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/earth_osm/eo.py", line 160, in save_osm_data
    region_tuple_list = [get_region_tuple(r) for r in region_list]
  File "/home/ubuntu/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/earth_osm/eo.py", line 160, in <listcomp>
    region_tuple_list = [get_region_tuple(r) for r in region_list]
  File "/home/ubuntu/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/earth_osm/gfk_data.py", line 172, in get_region_tuple
    id = get_id_by_str(region_str)
  File "/home/ubuntu/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/earth_osm/gfk_data.py", line 161, in get_id_by_str
    raise KeyError(f"{region_str} not found. Check eo.view_regions() or run 'earth_osm view regions'")
KeyError: "NA not found. Check eo.view_regions() or run 'earth_osm view regions'"

Note that

from earth-osm import eo
eo.save_osm_data(['namibia'], 'power', ['substation'])

works.

Expected behavior
It would be expected that 'NA' works as all other ISO codes.

Desktop (please complete the following information):

• OS: Linux, ubuntu 24.04, installed via pypsa-earth
• Version '2.3.post1'

Idea
Is 'NA' being drop by mistake as "Non-Applicable", much alike a Non-a-Number, in reading the gfk_index.csv somewhere down the pipeline?

[LRydin]

Original discussion on PyPSA-meets-Earth discord: https://discord.com/channels/911692131440148490/1331917268862504981