code: def test_train_create_loss(self):
      head = ranking_head.create_ranking_head(loss_fn=_make_loss_fn())
      # Create loss.
      training_loss = head.create_loss(
          features={},
          mode=tf_estimator.ModeKeys.TRAIN,
          logits=self._default_logits,
          labels=self._default_labels,
      )
      self.assertAllClose(self._default_loss, training_loss)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
  from tensorflow import estimator
  from tensorflow_ranking.python import head
  from tensorflow_ranking.python import metrics
label_desc: Use image node_id 6 for calling the RankingHeadTest obj's underlying member method code with example usage: obj.test_train_create_loss() without return types