I'm serving my tensorflow model in a Python bottle(or flask) framework but I would like to know how to enable the GPU.

This is how Im creating the session.

```
with tf.Session(graph=graph) as sess:
        np_pred_confs, np_pred_boxes = sess.run([pred_confs, pred_boxes], feed_dict=feed_dict_testing)

```

What should be changed to enable the use of the GPU as I'm running the code on a GPU machine.