Error in `Local Level - Nile.ipynb`

[spring-haru]

In Local Level - Nile.ipynb, running the following cell generated an error indicating @mc.stochastic() caused the problem

import pymc as mc

# Priors
prior_eps = mc.Gamma('eps', 0.5, 1)
prior_eta = mc.Gamma('eta', 0.5, 1)

# Create the model for likelihood evaluation
model = sm.tsa.UnobservedComponents(nile, 'local level')

# Create the "data" component (stochastic and observed)
@mc.stochastic(dtype=sm.tsa.statespace.MLEModel, observed=True)
def loglikelihood(value=model, eps=prior_eps, eta=prior_eta):
    return value.loglike([1 / eps, 1 / eta])

# Create the PyMC model
pymc_model = mc.Model((prior_eps, prior_eta, loglikelihood))

# Create a PyMC sample and perform sampling
sampler = mc.MCMC(pymc_model)
sampler.sample(iter=10000, burn=1000, thin=10)

I think this is because pymc changed its APIs.
I wonder if you have an idea of how to update the code to make it work.