Guide for gaussian process model

Thank you for the reply @fehiepsi but can you elaborate more detail. When I check the source code:

def guide(self):
        self.set_mode("guide")
        noise = self.get_param("noise")
        return noise 

But usually the guide is in the format like this:

def guide(data):
    # register a variational parameter with Pyro.
    alpha_q = pyro.param("alpha_q", torch.tensor(15.0),
                         constraint=constraints.positive)
    # sample latent_fairness from the distribution Exponential(alpha_q)
    pyro.sample("latent_fairness", dist.Exponential(alpha_q)

Why in the source code return noise (which I do not know what distribution it is) instead of pyro.sample(…dist.xxx)?