class_docstr: Keras callback integration.
  Pass an instance of this class to Keras model ``fit`` method as argument ``callbacks``.
  Keras will call relavent mehtods of this class to log metrics.
code: def on_epoch_end(self, epoch, logs=None):
      tracker.save(self._parse_logs(logs))
      logger.log()
  
file_path: labml/client/labml/utils/keras.py
imports: from typing import Dict, Optional
  import tensorflow
  from labml import tracker, logger
label_desc: Use image node_id 3 for calling the LabMLKerasCallback obj's underlying member method code with example usage: obj.on_epoch_end(epoch, logs) without return types