class_docstr: Fake subnetwork builder.
class_docstr_tok: ["Fake","subnetwork","builder","."]
code: def build_mixture_weights_train_op(
      self, loss, var_list, logits, labels, iteration_step, summary
  ):
      return
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  from adanet import tf_compat
  from adanet.subnetwork.generator import Builder
  from adanet.subnetwork.generator import Subnetwork
  import tensorflow.compat.v2
label_desc: Use image node_id 4 for calling the FakeSubnetwork obj's underlying member method code with example usage: obj.build_mixture_weights_train_op(loss, var_list, logits, labels, iteration_step, summary) without return types