def add_metrics(self, metrics):
        raise NotImplementedError()
Hacky way of computing the predictive log likelihood
dataset/ETHPy150Open kiip/statsite/statsite/aggregator.py/Aggregator.add_metrics--crossover with--dataset/ETHPy150Open HIPS/pgmult/pgmult/particle_lds.py/ParticleSBMultinomialLDS.predictive_log_likelihood