[x] copy/ change and adjust code to work as python function
[x] make sure to add docstring in the sphinx format (see for example util/util.py - read_summa_workflow_control_file or data_specific_processing/merit.py)
[x] Add to the description parts of the readme.rst file that come with the summa-cwarhm script that are relevant to understand what the function does precisely.
[x] point test_bow_at_banff.py to use the function instead of the wrapper