Fair enough. For me the "brilliance" comes in how readable it comes out to be; I find it far easier to scan through and understand (without even looking at the brk() function to see what it does) the first time through then the sentinel approach. My syntax suggestion came from thinking about how to make it even more readable (providing one can swallow the "this decorator automatically becomes a context manager" part-- which might be too hard to swallow I don't know).

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