def METHOD_NAME(rng, params, images):
  """Monte Carlo estimate of the negative evidence lower bound."""
  enc_params, dec_params = params
  mu_z, sigmasq_z = encode(enc_params, images)
  logits_x = decode(dec_params, gaussian_sample(rng, mu_z, sigmasq_z))
  return bernoulli_logpdf(logits_x, images) - gaussian_kl(mu_z, sigmasq_z)