code: def get_optimizer(self):
      return self.optimizer()
  
imports: import numpy
  import tensorflow
  from tensorpack import BatchNorm, DataFlow, ModelDescBase, StagingInput, TowerTrainer, argscope
  from tensorpack.graph_builder import DataParallelBuilder, LeastLoadedDeviceSetter
  from tensorpack.tfutils.summary import add_moving_summary
  from tensorpack.tfutils.tower import TowerContext, TowerFunc
  from tensorpack.utils import logger
  from tensorpack.utils.argtools import memoized_method
label_desc: Use image node_id 4 for calling the GANModelDesc obj's underlying member method code with example usage: obj.get_optimizer() and returns: self