class_docstr: A hook for running a train op separate from the main session run call.
class_docstr_tok: ["A","hook","for","running","a","train","op","separate","from","the","main","session","run","call","."]
code: def before_run(self, run_context):
      run_context.session.run(self._train_op)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import inspect
  from adanet import subnetwork
  from adanet import tf_compat
  import tensorflow.compat.v2
label_desc: Use image node_id 2 for calling the _SecondaryTrainOpRunnerHook obj's underlying member method code with example usage: obj.before_run(run_context) without return types