Count the number of events in a dataset

Hi, do we normalize the samples to their cross-sections in such a way that:

\sigma(\mathrm{fb}) \times \mathcal{L}(\mathrm{fb}^{-1}) / (\mathrm{N_{positive}}-\mathrm{N_{negative}})

If so, I think we should have the function to count the positive/negative number of events for the processed datasets.

I didn't notice there is such functionality. I could add this if necessary. This should be easy to add.