This has no semantic impact as the class is guarded with a hasattr()
check; this is being done to keep typing.py in sync between Python 3.5
and 3.6 as requested by Guido.
This syncs to rev 7b43ada77821d23e55e3a4b35f6055a59b9e1ad7 there.
Summary:
- Add typing.DefaultDict (as a generic variant of collections.defaultdict).
- Use collections.Reversible if it exists (only relevant for Python 3.6).
- Revamped generic class behavior to conform to updated PEP 484.
- Improve speed of Generic.__new__.
- Make sure __init__ is called for new Generic instances. Fix issue #26391.
- Refactor async support to be compatible with 3.2, 3.3, 3.4.
- Remove 'io' and 're' from __all__ (they still exist, just not
included by "import *"). Fix issue #26234.
- Change @overload -- you can now use it outside stubs (you still
cannot call the decorated function though).
There area bunch of TODOs here, but the biggest (not mentioned in the
file) is that I'm going to take out __instancecheck__ and
__subclasscheck__. However my personal schedule is such that I
probably won't have time for these before Larry tags beta 1. But I
will try -- this commit is mostly to make sure that typing.py doesn't
completely miss the train.
PS. I'm tracking issues at https://github.com/ambv/typehinting/issues.
Guido van Rossum
Brett Cannon
Guido van Rossum