code: def step(self):
      self._optimizer.step()
  
imports: from typing import Union, Literal, Tuple
  import torch
  from fate.arch import Context
  from fate.ml.nn.model_zoo.agg_layer.agg_layer import _AggLayerBase
  from fate.arch.protocol.mpc.nn.sshe.nn_layer import SSHENeuralNetworkAggregatorLayer, SSHENeuralNetworkOptimizerSGD
label_desc: Use image node_id 7 for calling the SSHEAggLayerGuest obj's underlying member method code with example usage: obj.step() without return types