Support default values for collections.namedtuple?

[ilevkivskyi]

Python 3.7 adds support for specifying default values in call to collections.namedtuple, see python/cpython#4859. So for example this is valid:

from collections import namedtuple

NT = namedtuple('NT', ('x', 'y'), defaults=(0, 0))
NT()
NT(1)
NT(1, 2)

Should we support this, or supporting default values for typing.NamedTuple (already implemented) is enough?

[gvanrossum]

The short form of collections.namedtuple is very popular (ask @rhettinger) and I think we should make it as easy as possible to translate its use to typing.NamedTuple. So I think we should support it.

[JukkaL]

I agree with @gvanrossum. Also, this doesn't look like a lot of work to implement. Tagging as high priority since 3.7 release date is pretty close.

[JelleZijlstra]

Fixed by #5215.