Why can function definitions only use identifiers, and not attribute references or any other primaries?

[Jeremy Banks]

On Thu, Apr 23, 2009 at 13:03, John Krukoff <jkrukoff at ltgc.com> wrote:
> You probably want to be searching for multi-line lambda to find the past
> decade or so of this argument, as that's where most people who argued
> for this came from. But, if you'd just like a bit of discouragement,
> here's GvR arguing that there's just no good way to mix statements and
> expressions in python:
> http://www.artima.com/weblogs/viewpost.jsp?thread=147358

I've read those discussion before, but somehow never made the
connection between those and this. I'll give that article a read, it
probably details exactly the perspective I'm looking for. Thank you!