Understanding Python's Import Engine

[MysticaL]

Hi,

I have a question pertaining to importing post python 3.4 (I am using python 3.8). It is my understanding that the import engine will internally invoke meta path finders in sys.meta_path, of which the third PathFinder is used to find modules using sys.path. Given the following file structure, with "test" and "a" being namespace packages,

example/test/a/b.py

If I run an interpreter with cwd as example, the following code fails:

>>> import test.a
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'test.a'

My question is, since the test builtin does not have a module "a", why does the third PathFinder fail to find the module, as the FileFinder with cwd should be able to locate the module?