def _make_example_generator(self):
        """Returns a :class:`TFExampleGenerator` instance that will generate
        ``tf.train.Example`` protos for this exporter.
        """
        raise NotImplementedError(
            "subclasses must implement _make_example_generator()"
        )
Returns a :class:`TFExampleGenerator` instance that will generate
        ``tf.train.Example`` protos for this exporter.
        
fiftyone/utils/tf.py