[parrt]

True, but you have to do it one at a time to look at the variables. Also, the exception message doesn't tell you which operator among several is the issue. This just makes it easier. :)

[blackbear_]

Of course, but debugging is a general skill that will work in every case.

Not trying to detract anything from this tool, I'll definitely give it a try it next time I have something that doesn't work :)