code: def optimizer(self):
      lr = tf.get_variable(
          "learning_rate", initializer=5e-3, trainable=False
      )
      return tf.train.AdamOptimizer(lr)
  
file_path: tensorpack/examples/boilerplate.py
imports: import argparse
  import os
  import tensorflow
  from tensorpack import *
label_desc: Use image node_id 3 for calling the Model obj's underlying member method code with example usage: obj.optimizer() and returns: tf