Add docstrings to python methods and functions

[RussellManser-NCO]

What is wrong?

Many python methods and functions in the package are missing docstrings or the docstrings are incomplete. Docstrings assist in debugging, particularly when the types of arguments and return values are documented.

What should have happened?

Scripts should include docblocks (general application standards), which implies documenting methods/functions as well.

Please add docstrings to methods/functions in the following scripts:

• grib2writer.py
• run_graphcast.py
• gen_aigfs_ics.py
• gen_aigefs_ics.py

If a description of arguments and return values are missing from existing docstrings, please add them.

Steps to reproduce

N/A

Bugzilla issue

No response

Additional information

No response

Do you have a proposed solution?

No response