Add systematics in ProfileLikelihoodCalculator

Dear All,

I’m trying to add a systematics uncertainty on the number of signal events (coming from a fit) before calculating the upper limit on the signal using profile likelihood.
I’m using an observables-based analysis as described in: … e_Gaussian
but I don’t understand how it’s possible to add a systematics on the number of signal events? Can you give me an example, please?