How to modify subpackage in django project

I am running into a problem that I need to change a subpakcage of a big third party package. the big package, lets say foo, includes many subpackages, and I want to modify one of them, lets say bar. After weighing many options, I decide to dynamically change sys.modules when my django project

Modify a subpackage behavior

I am running into a problem that I need to change a subpakcage of a big third party package in django. the big package, lets say foo, includes many subpackages, and I want to modify one of them, lets say bar. After weighing many options, I decide to dynamically change sys.modules when my djang