New syntax `Trailing Block` for constructing objects with complex structure

[jcampbell05 (James Campbell)]

I’ve gone ahead and split my proposal off into it’s own thread as it feels like it’s a separate topic

Introduce support for trailing closures

In many languages trailing closures are a feature designed to improve readability when you need to pass a function a reference to another function to act as a callback, as part of constructing aDSL dynamically or part of functional programming. Currently I believe the way handles these kinds of paradigm goes against the first four lines of PEP 20 Firstly, if you want a function to have a callback you have two options: Pass in the name of a function def callback(*args): print("do some th…