* Compiling a string annotation containing a lambda with keyword-only
argument without default value caused a crash.
* Remove the final "*" (it is incorrect syntax) in the representation of
lambda without *args and keyword-only arguments when compile from AST.
* Improve the representation of lambda without arguments.
* Document `from __future__ import annotations`
* Provide plumbing and tests for `from __future__ import annotations`
* Implement unparsing the AST back to string form
This is required for PEP 563 and as such only implements a part of the
unparsing process that covers expressions.
Serhiy Storchaka
Stéphane Wirtel
Guido van Rossum