Python 3 treats an empty i18n directory as an implicit namespace package (PEP 0420).
This causes i18n.messages_available to return True and twget to cause a AttributeError:
File "/home/ubuntu/pywikibot-core/tests/l10n_tests.py", line 67, in __new__ keys = i18n.twget_keys(package) File "/home/ubuntu/pywikibot-core/pywikibot/i18n.py", line 619, in twget_keys pathname = os.path.join(os.path.dirname(mod.__file__), package) AttributeError: 'module' object has no attribute '__file__'