class_docstr: Callback base class. 
code: def on_batch_end(self, training_state, snapshot=False):
      pass
  
imports: from __future__ import division, print_function, absolute_import
  import time
  import sys
label_desc: Use image node_id 7 for calling the Callback obj's underlying member method code with example usage: obj.on_batch_end(training_state, snapshot) without return types