'returns **kwargs parameters for model.fit()
to enable all callbacks.  e.g.
model.fit(X=train, eval_data=test, **pdlogger.callback_args())'

def callback_args(self):

    return {'batch_end_callback': self.train_cb, 'eval_end_callback': self.eval_cb, 'epoch_end_callback': self.epoch_cb}
