def restore_model(self, directory=None, file=None):
self.model.restore(directory=directory, file=file)<EOL>
Restore TensorFlow model. If no checkpoint file is given, the latest checkpoint is
restored. If no checkpoint directory is given, the model's default saver directory is
used (unless file specifies the entire path).

Args:
    directory: Optional checkpoint directory.
    file: Optional checkpoint file, or path if directory not given.