code: def optimizer(self):
      opt = tf.train.RMSPropOptimizer(1e-4)
      return opt
  
      # An alternative way to implement the clipping:
      """
          from tensorpack.tfutils import optimizer
          def clip(v):
              n = v.op.name
              if not n.startswith('discrim/'):
                  return None
              logger.info("Clip {}".format(n))
              return tf.clip_by_value(v, -0.01, 0.01)
          return optimizer.VariableAssignmentOptimizer(opt, clip)
          """
  
file_path: tensorpack/examples/GAN/WGAN.py
imports: import tensorflow
  from tensorpack import *
  from tensorpack.tfutils.summary import add_moving_summary
  import DCGAN
  from GAN import SeparateGANTrainer
label_desc: Use image node_id 2 for calling the Model obj's underlying member method code with example usage: obj.optimizer() and returns: opt