title: Does Keras ModelCheckpoint save the best model across multiple fitting sessions?
body: <p>If I have a Keras model fitted with the <code>ModelCheckpoint</code> callback and fit it in several 'fitting sessions' (i.e. I call <code>model.fit()</code> multiple times), will the callback save the best model in the most recent fitting session or the best model out of all fitting sessions?</p>
  <p>Thanks.</p>