Odoo is the world's easiest all-in-one management software. It includes hundreds of business apps:
CRM | e-Commerce | Accounting | Inventory | PoS | Project management | MRP | etc.
You can use the following method for implementing on_change method multiple fields with just one function.The fields must be in the same model.
<field name='test' on_change="get_func(test,'string')"/>
#and in python use
""here you can compare the field name and exec the desired lines using the if """