I'll work on code formatting and the error checking and other cleanup. Open to other names than tname and
vname, I created those non-terminals in order to use the same code for processing "def" and "lambda". Terminals 
are caps IIUC. 

I did add a test for the multi-paren situation. 2.5 had that bug too.

Re: no changes to ceval, I tried generating the func_annotations dictionary using 
bytecodes. That doesn't change the ceval loop but was more code and was slower. 
So there is a way to avoid ceval changes.

Re: deciding if lambda was going to require parens around the arguments,
I don't think there was any decision, and yes annotations would be easily supportable.
Happy to change if there is support, it's backwards incompatible.

Re: return type syntax, I have only seen the -> syntax (vs a keyword 'as') on Guido's blog.

Thanks for the comments!