class_docstr: Hook to run assign_ops.
code: def before_run(self, run_context):
      del run_context
      update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS)
      return tf.train.SessionRunArgs(update_ops)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the UpdateOpsHook obj's underlying member method code with example usage: obj.before_run(run_context) and returns: tf