KeyError: nchunks in rule prepare_gas_network

[doneachh]

Checklist

• [ ] I am using the current main branch or the latest release. Please indicate.
• [ ] I am running on an up-to-date pypsa-africa environment. Update via conda env update -f envs/environment.yaml.

Describe the Bug

Due to the new rule prepare_gas_network, nchunks has to be in the config.default again

Error Message

INFO:snakemake.logging:
/home/aca39878/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/pypsa/networkclustering.py:16: UserWarning: The namespace `pypsa.networkclustering` is deprecated and will be removed in PyPSA v0.24. Please use `pypsa.clustering.spatial instead`. 
  warnings.warn(
/home/aca39878/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/pypsa/networkclustering.py:16: UserWarning: The namespace `pypsa.networkclustering` is deprecated and will be removed in PyPSA v0.24. Please use `pypsa.clustering.spatial instead`. 
  warnings.warn(
/home/aca39878/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/pypsa/networkclustering.py:16: UserWarning: The namespace `pypsa.networkclustering` is deprecated and will be removed in PyPSA v0.24. Please use `pypsa.clustering.spatial instead`. 
  warnings.warn(
Traceback (most recent call last):
  File "/mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/.snakemake/scripts/tmp0dmp6trg.prepare_gas_network.py", line 905, in <module>
    bus_regions_onshore = load_bus_region(snakemake.input.regions_onshore, pipelines)[0]
  File "/mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/.snakemake/scripts/tmp0dmp6trg.prepare_gas_network.py", line 552, in load_bus_region
    nchunks = config_pypsa_earth["build_shape_options"]["nchunks"]
  File "/home/aca39878/anaconda3/envs/pypsa-earth/lib/python3.10/site-packages/ruamel/yaml/comments.py", line 852, in __getitem__
    return ordereddict.__getitem__(self, key)
KeyError: 'nchunks'
[Thu Feb  1 16:46:44 2024]
INFO:snakemake.logging:[Thu Feb  1 16:46:44 2024]
Error in rule prepare_gas_network:
    jobid: 24
    input: /mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/pypsa-earth/resources/bus_regions/regions_onshore_elec_s_10.geojson
    output: resources/gas_networks/gas_network_elec_s_10.csv, resources/gas_networks/existing_gas_pipelines__10.png, resources/gas_networks/clustered_gas_pipelines__10.png

ERROR:snakemake.logging:Error in rule prepare_gas_network:
    jobid: 24
    input: /mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/pypsa-earth/resources/bus_regions/regions_onshore_elec_s_10.geojson
    output: resources/gas_networks/gas_network_elec_s_10.csv, resources/gas_networks/existing_gas_pipelines__10.png, resources/gas_networks/clustered_gas_pipelines__10.png

RuleException:
CalledProcessError in file /mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/Snakefile, line 128:
Command 'set -euo pipefail;  /home/aca39878/anaconda3/envs/pypsa-earth/bin/python3.10 /mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/.snakemake/scripts/tmp0dmp6trg.prepare_gas_network.py' returned non-zero exit status 1.
  File "/mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/Snakefile", line 128, in __rule_prepare_gas_network
  File "/home/aca39878/anaconda3/envs/pypsa-earth/lib/python3.10/concurrent/futures/thread.py", line 58, in run
ERROR:snakemake.logging:RuleException:
CalledProcessError in file /mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/Snakefile, line 128:
Command 'set -euo pipefail;  /home/aca39878/anaconda3/envs/pypsa-earth/bin/python3.10 /mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/.snakemake/scripts/tmp0dmp6trg.prepare_gas_network.py' returned non-zero exit status 1.
  File "/mnt/c/Users/aca39878/Documents/Git/Namibia/pypsa-earth-sec/Snakefile", line 128, in __rule_prepare_gas_network
  File "/home/aca39878/anaconda3/envs/pypsa-earth/lib/python3.10/concurrent/futures/thread.py", line 58, in run