Based on patches by Konstantin Molchanov and Neil Girdhar.

Patch by James Pickering.

Patch by Jason Fried.

It was documented since 07a5610bae9d.

Initial patch by Roger Luethi.

Reformat header above separator line (added if missing) to a common format.
Patch by Yoni Lavi.

Patch by David Coles.

Patch by Łukasz Langa.

This is how paste work on Windows, Mac, modern Linux apps, and ttk widgets.
The exception was X11 tk widgets.  Original patch by Serhiy Storchake.

Initial patch by ingrid.

  unused and outdated icons.

Patch by Arthur Carcano.

a negative number without setting an exception.

(Upstream is https://github.com/python/typing)

- Add TYPE_CHECKING (false at runtime, true in type checkers) (upstream #230).
- Avoid error on Union[xml.etree.cElementTree.Element, str] (upstream #229).
- Repr of Tuple[()] should be 'Tuple[()]' (upstream #231).
- Add NewType() (upstream #189).

It will probably be added back in Python 3.6, once its compatibility
issues are resolved; see [1] for more details.

[1] https://mail.python.org/pipermail/async-sig/2016-June/000045.html