code: def setUp(self):
      super().setUp()
  
      patch = tf.test.mock.patch(
          "tensorflow.compat.v1.Session", wraps=tf.Session
      )
      patch.start()
      self.addCleanup(patch.stop)
  
      class Squarer(op_evaluator.PersistentOpEvaluator):
          def __init__(self):
              super().__init__()
              self._input = None
              self._squarer = None
  
          def initialize_graph(self):
              self._input = tf.placeholder(tf.int32)
              self._squarer = tf.square(self._input)
  
          def run(self, xs):  # pylint: disable=arguments-differ
              return self._squarer.eval(feed_dict={self._input: xs})
  
      self._square = Squarer()
  
file_path: tensorboard/tensorboard/util/op_evaluator_test.py
imports: import tensorflow.compat.v1
  from tensorboard.util import op_evaluator
label_desc: Use image node_id 1 for calling the PersistentOpEvaluatorTest obj's underlying member method code with example usage: obj.setUp() and returns: self