class_docstr: Experimental class that wraps keepsake.init() and
  experiment.checkpoint() in a Keras callback.
code: def on_train_begin(self, logs=None):
      self.experiment = init(path=".", params=self.init_params)
      super().on_train_begin(logs)
  
file_path: keepsake/python/keepsake/keras_callback.py
imports: from typing import Optional, Dict, Any, Tuple
  from .None import init
  from .experiment import Experiment
  from .project import Project
label_desc: Use image node_id 2 for calling the KeepsakeCallback obj's underlying member method code with example usage: obj.on_train_begin(logs) without return types