def set_label(self, s, label):
        self.state.body_labels[self.bodies[self.index].segment_id] = label
        self.set_index(self.index + 1)
def forward(self, x):
        mean_x = self.mean_module(x)
        covar_x = self.covar_module(x)
        return MultivariateNormal(mean_x, covar_x)