Run into a problem regarding math.random

**Code:**

self.RotAngle = self.RotAngle - math.rad(math.random((a*-200) + 1, (a*200) + 1)/200)

Where

a is a number generated between 0 and 6. However if the number generated is 0, I get an error that the second argument of the math.random() is empty.

Error generated is

:bad argument #2 to 'random' (Interval is empty)

so to counteract this I tried adding +1 in both arguments, but alas does nothing to prevent the error.

Maybe I'm completely misinterpreting what the error actually is saying?