...
https://github.com/openimis/openimis-be-policy_py/blob/develop/policy/values.py
convert(from, to, obj_from, **agrsagrv)
from = ‘Contract' / 'Policy’
to = 'Invoice'
argv (for all invoices, ) obj_from policy/contract obj, date_from, date_to,, product_id, location
Registration on signals from other module(existing or not):
...