I noticed that __init__ creates an unnecessary copy of initlist.data:

self.data[:] = initlist.data[:]

and __iadd__ converts its second argument to list in some cases:

self.data += list(other)

I removed the slice part from the former, but I'm wondering if self.data += list(other) has any advantages over self.data += other.

LGTM.

@vaultah Could you add your name in Misc/ACKS, and add "Patch by " in NEWS entry?

@rhettinger Would you review this?

My name is already in Misc/ACKS. I'm not interested in updating this patch. If it's possible, you may merge it without a name or under your name.

:( I'm sorry, didn't know this was out there since it wasn't attached to the ticket. Will review what you have done as it seems to be more than what Erick Cervantes and I had and will use what is valid. Most of all, I will make sure your name is listed some where as contributing to this, as soon as I find out where that some where is. Thank you for your efforts!

I have reviewed the changes and it in addition to resolving the problem stated in ticket 27639, there are two other changes. One, in init, you identify above. My team agrees that this change is a good performance improver.

The second one involves what appears to be a modification to _setitem that corresponds to the modification to getitem. The problem is that it is unclear why setitem needs to be modified. It works fine without any changes. Vaultah, I would very much like for you to explain it to me.