ENH: Fixing some types

[ThibaultDECO]

Fixing some types

[rhshadrach]

Thanks for the PR. Improving the type-hints would certainly be welcome, but it seems the changes here are either incorrect or equivalent to the type-hints that are already there.

[rhshadrach]

Removing str here is incorrect, index_col can be a string.

[ThibaultDECO]

@rhshadrach Thanks for having looked at it!
io is not the same as io: Any, it is equivalent to io: Unknown
Same for list and Callable
I'll have a look at str for index_col, but it seemed to me that index_col could not function with str and other functions (such as parse) only accept int.

[rhshadrach]

io is not the same as io: Any, it is equivalent to io: Unknown

Ah, with pyright but not mypy, sure. But in either case I'm not really seeing a benefit to adding Any here.