Slightly tangential, but I've found importlinter neat for restricting what layers in your Python code can call each other (in this case by restricting imports, not calls): https://pypi.org/project/import-linter/

For example, you can ensure lower-level packages don't import higher-level ones:

  [importlinter:contract:my-layers-contract]
  name = Layered architecture
  type = layers
  layers =
      mypackage.cli       # can import anything
      mypackage.services  # can't import from mypackage.cli
      mypackage.models    # can't import from .cli or .services