Since os is a module instead of a package, import os.path should fail. For comparison: >>> import os.sys Traceback (most recent call last): File "<python-input-0>", line 1, in <module> import os.sys ModuleNotFoundError: No module named 'os.sys'; 'os' is not a package Note that os.sys is available: >>> import os >>> os.sys <module 'sys' (built-in)> So, how does import os.path work? Are there any other cases of something like this? Continue reading...