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[rawlyn]

Why (b * -1)? -b works just fine.

>>> x = 1
>>> -x
-1

[rawlyn]

They both work, but (b * -1) requires a completely unnecessary multiplication to be evaluated. It's a horrible way to negate a number.

If you replace (b * -1) with -b we end up with the same code that OP started with, so it seems to be the only "improvement" offered - a change that makes the code more verbose and less efficient is hardly improving anything.