code: def optimizer(self):
      lr = tf.get_variable(
          "learning_rate", initializer=5e-3, trainable=False
      )
      opt = tf.train.AdamOptimizer(lr, epsilon=1e-3)
      return optimizer.apply_grad_processors(
          opt, [GlobalNormClip(5), SummaryGradient()]
      )
  
file_path: tensorpack/examples/CTC-TIMIT/train-timit.py
imports: import argparse
  import os
  import tensorflow
  from tensorpack import *
  from tensorpack.tfutils.gradproc import GlobalNormClip, SummaryGradient
  from timitdata import TIMITBatch
label_desc: Use image node_id 3 for calling the Model obj's underlying member method code with example usage: obj.optimizer() and returns: optimizer