code: def _get_fractions_summary_key(subnetwork_index):
      return (
          "mixture_weight_fractions/adanet/adanet_weighted_ensemble/subnetwork_%s"
          % subnetwork_index
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import contextlib
  from absl.testing import parameterized
  from adanet import ensemble
  from adanet import subnetwork
  from adanet import tf_compat
  from adanet.core.summary import Summary
  import mock
  import tensorflow.compat.v2
  from tensorflow.python.eager import context
  from tensorflow.python.framework import test_util
label_desc: Use image node_id 2 for calling a global function with example usage: _get_fractions_summary_key(subnetwork_index) and returns: unknown