code: def step(self, state, y=None):
      self.t += 1
  
      # Proposal distribution
      pyro.sample(
          "z_{}".format(self.t),
          dist.Normal(
              state["z"].matmul(self.model.A), torch.tensor([1.0, 1.0])
          ).to_event(1),
      )
  
file_path: pyro/examples/smcfilter.py
imports: import argparse
  import logging
  import torch
  import pyro
  import pyro.distributions
  from pyro.infer import SMCFilter
label_desc: Use image node_id 3 for calling the SimpleHarmonicModel_Guide obj's underlying member method code with example usage: obj.step(state, y) without return types