code: def afterOptimizerStep(
      self, retrievedPosIndexes, retrievedNegIndexes=None
  ):
      torch.cuda.synchronize()
  
      reshapedRetrieval = self._getReshapedRetrieval(
          retrievedPosIndexes, retrievedNegIndexes
      )
  
      for idx, optVar in enumerate(self.optVarList):
          self.pytorchGPUVar[idx][
              reshapedRetrieval
          ] = self.given_optimizer.state_dict()["state"][
              self.optimizerKey
          ][
              optVar
          ]
  
imports: import torch
  import os
  import numpy
label_desc: Use image node_id 4 for calling the GPUPytorchOptimizerFactory obj's underlying member method code with example usage: obj.afterOptimizerStep(retrievedPosIndexes, retrievedNegIndexes) without return types