Given a metric tensor, is there a quick way to find the signature of the metric?

I am trying to calculate the Weyl Scalars for the Kerr metric and I get an error

"Error, (in simplify/recurse) numeric exception: division by zero"

restart;
with(Physics);
with(Tetrads);
g_[[5, 29, 1]];
WeylScalars(TransformTetrad(canonicalform));

When I try: 
Weyl[scalars];

It gives me the weyl scalars  but they dont look correct because some of the scalars are supposed to be zero for a type D spacetime.

When I look for petrov type II vacuum solutions in the Metric search, one of the metrics i get is Stephani [33,8,3].

But when I load the metric and calculate the Ricci or the Einstein tensor, they are not identically zero.
Am I using the metric search wrong or is there a glitch in the program?

Download Temp.mw

In the metric search command in the differential gometry package, you can use the petrov type of the Plebanski Tensor as a selection criteria.

But if you had a form of a metric tensor, how do you go about finding the petrov type of the Plebanski Tensor?

I know trig functions are hard to simplify in general but was wondering if there was any simplification command that comes in handy for trig functions of the following form.

sin(theta)^(A - 2)*cos(theta)^2 - sin(theta)^(A - 2) + sin(theta)^A