'Saves a checkpoint of the model and a .npz file with stored rewards.
Args:
name: String name to use for the checkpoint and rewards files.
directory: Path to directory where the data will be saved. Defaults to
self.output_dir if None is provided.'

def save_model(self, name, directory=None):

    if (directory is None):
        directory = self.output_dir
    save_loc = os.path.join(directory, name)
    self.saver.save(self.session, save_loc, global_step=(len(self.rewards_batched) * self.output_every_nth))
    self.save_stored_rewards(name)
