Custom importer and errors

[Fips]

Hi folks!

I'd like to split my package tree into several IDE projects and build a custom importer to import
'top.child1.child2'
from the directory
<python-path-entry>/top.child1.child2/__init__.py
so basically replacing the dots with slashes and having the package content lying directly in the project folder. I have come up with this:

# usercustomize.py

import sys
from importlib.machinery import ModuleSpec
from pathlib import Path

Loader = type(__spec__.loader)

class IdeHelper:
    @classmethod
    def find_spec(cls, name, path, target=None):
        for dirname in sys.path:
            dirobj = Path(dirname)
            if dirobj.name == name:
                break
        else:
            return None
        origin = str(dirobj.joinpath('__init__.py').absolute())
        ret = ModuleSpec(name, Loader(name, origin), origin=origin)
        return ret

sys.meta_path.append(IdeHelper)

which I'm on the right direction with. Unfortunately, I'm getting errors while importing a subpackage. With 'import top.child1' the error is

Error:
ModuleNotFoundError: No module named 'top.child1'; 'top' is not a package

whereas with 'from top import child1' the error changes to

Error:
ImportError: cannot import name 'child1' from 'top' (unknown location)

How can I make this work?

Best wishes,
Fabiano