Fix mypy error in pandas\tests\indexes\interval\test_interval_tree.py
- [x] relates to #28926
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Hello @pqzx! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2019-11-06 23:07:39 UTC Hmm just out of curiosity does this work if you did `(list(x) for x in permutations(range(3)))`. Assuming equivalent I think would be easier to track than the type ignore > 
> 
> Hmm just out of curiosity does this work if you did `(list(x) for x in permutations(range(3)))`. Assuming equivalent I think would be easier to track than the type ignore

Yes, this works. Updated to use this instead. @pqzx can you fix lint error and merge master @simonjayhawkins sorry for the noob question, what's the lint error in this case? Is it the line length? Looks like the checks are fine. I think if you merge master and try again should work (have had intermittent failures recently) @WillAyd OK to merge? Thanks @pqzx !