code: def head():
      from tensorflow_estimator.python.estimator.head import (
          regression_head,
      )  # pylint: disable=g-direct-tensorflow-import,g-import-not-at-top
  
      return regression_head.RegressionHead(
          loss_reduction=tf_compat.SUM_OVER_BATCH_SIZE
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import shutil
  import struct
  import sys
  from absl import flags
  from absl.testing import parameterized
  from adanet import ensemble
  from adanet import subnetwork
  from adanet import tf_compat
  from adanet.core.architecture import _Architecture
  from adanet.core.candidate import _Candidate
  from adanet.core.ensemble_builder import _EnsembleSpec
  from adanet.core.ensemble_builder import _SubnetworkSpec
  from adanet.core.eval_metrics import _EnsembleMetrics
  from adanet.core.eval_metrics import _IterationMetrics
  from adanet.core.eval_metrics import _SubnetworkMetrics
  import tensorflow.compat.v2
label_desc: Use image node_id 7 for calling a global function with example usage: head() and returns: regression_head