code: def est_kl_divergence(self, other, kernel=None, delta=1e-2):
          
          return self._kl_divergence(
              other.particle_locations,
              other.particle_weights,
              kernel, delta
          )
docs: Finds the KL divergence between this and another particle
          distribution by using a kernel density estimator to smooth over the
          other distribution's particles.
  
          :param SMCUpdater other: