* https://pypi.org/project/executor/ for spawning processes?

* to make processing of RDF deterministic:
  https://github.com/koo5/univar/blob/master/pyin/ordered_rdflib_store.py

* Don't download URL twice if they differ only in #ID in the end of the URL.

* How to "import" in Python through the network:
  https://docs.python.org/3/reference/import.html#replacing-the-standard-import-system

* https://deb-pkg-tools.readthedocs.io/en/latest/

* --before cmdline option to set order of precedences

* ScriptsIterator should remember the message with the reason it stopped for.
