Great cleanup!

[sobolevn]

I've searched for duplicate definitions and removed most of them.
This was a manual job with some help of a new stubtest.

Rules:

• I haven't touched any magic methods (except a couple of identical __init__)
• I haven't touched any code with comments
• I haven't touched untyped code
• I haven't touched overloads, because they are too hard to read and verify
• I haven't touched any other advanced stuff

[AlexWaygood]

Can we maybe also leave the ones that are explicitly marked as Incomplete as they are? Since we've explicitly marked these as "we haven't figured out what they're meant to be yet", they might plausibly have different types in the subclass than in the superclass at runtime.

[sobolevn]

I want to cancel all changes in this file :)
Because after my merge conflict I stopped understanding what is going on.

[sobolevn]

This error looks like a stubtest bug to me:

error: io.BufferedRandom.seek is inconsistent, stub argument "__offset" differs from runtime argument "target"
Stub: at line 65
def (self: io.IOBase, builtins.int, builtins.int =) -> builtins.int
Runtime:
def (self, target, whence=0, /)

Both types have pos-only parameters, but for some reason they are reported as incompatible.
I will restore these two with a comment for now.

[AlexWaygood]

This error looks like a stubtest bug to me:

I believe it's actually stubtest working as intended; see python/mypy#13113. I can see both sides of the argument here :-)

[AlexWaygood]

I haven't rigorously checked the whole thing to see if the signatures on subclasses are identical to the ones on superclasses, but I trust you to have done it properly :)

LGTM, though I'll wait to see if any other maintainers have any thoughts before merging.

[sobolevn]

I trust you to have done it properly

I trust stubtest more than myself here 😆

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[sobolevn]

Any other feedback? :)

I think that this PR can quickly have merge conflicts and this will require some time to re-think.

[srittau]

Not checked this in depth, either, but the passing tests give me confidence.