Some months ago I saw slides about how deffered work in Twisted.
If I remember correctly these there two columns on yellow background,
with pictures on the right, which described how errback processing
propogates and how to handle deferreds.
Does anybody remember them? I looks like color codes for the blocks
on the diagrams were filled bright green and solid bright red square
blocks. I can't find them, does anybody know where I could see them?