I would expect the following to work:
```
>>> import pathlib
>>> pathlib.Path.cwd().parents[0:1]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "...\Python36\lib\pathlib.py", line 593, in __getitem__
    if idx < 0 or idx >= len(self):
TypeError: '<' not supported between instances of 'slice' and 'int'
```

Since pathlib documents `parents` as a sequence-type, and slicing a sequence is pretty standard behavior.

If it is deemed a bug which needs to be fixed, I've gone ahead and attached the PR to fix it.

CLA signage is pending approval at the company I work for, with most people out for the holidays (so it might be a day or two turnaround).

See also issue21041. First than add support for slices, we should make a decision about negative indices.


In any case this is a new feature, which can be only added in the future 3.8 release.

Just commented on the related issue: https://bugs.python.org/issue21041#msg352281 

My question is: Why would you need to slice parents? parents already looks like the result of some slice.

Pretty much the same reason you would want to slice any other sequence. You want some range of values.

top_most_3_dirs = myPath.parents[-3:]
grandparents_and_beyond = myPath.parents[1:]

The same goes for negative indexes.