code: def on_sub_batch_end(self, training_state, train_index=0):
      for callback in self.callbacks:
          callback.on_sub_batch_end(training_state, train_index)
  
imports: from __future__ import division, print_function, absolute_import
  import time
  import sys
label_desc: Use image node_id 6 for calling the ChainCallback obj's underlying member method code with example usage: obj.on_sub_batch_end(training_state, train_index) without return types