You've really only given one reason why braces are a good idea:
I also appreciate single lined conditional or loops once in a while.
Not only is this argument even weaker than the two you yourself gave in
defense of whitespace, these two features are already supported in Python.
If you're not
This is my first post to python-dev, so for those who might not know
me, I'm the author of Pro Django and more recently, Pro Python.
I haven't looked at the plugin landscape in a while, but I was very
disappointed the last time I looked at how complex typical systems
were in this regard. There
