docstr: Test accumulator by writing values and then reading them.
code: def testGraphFromMetaGraphBecomesAvailable(self):
      """Test accumulator by writing values and then reading them."""
  
      directory = os.path.join(
          self.get_temp_dir(), "metagraph_test_values_dir"
      )
      if tf.io.gfile.isdir(directory):
          tf.io.gfile.rmtree(directory)
      tf.io.gfile.mkdir(directory)
  
      writer = test_util.FileWriter(directory, max_queue=100)
  
      with tf.Graph().as_default() as graph:
          _ = tf.constant([2.0, 1.0])
      # Add a graph to the summary writer.
      meta_graph_def = tf.compat.v1.train.export_meta_graph(
          graph_def=graph.as_graph_def(add_shapes=True)
      )
      writer.add_meta_graph(meta_graph_def)
  
      writer.flush()
  
      # Verify that we can load those events properly
      acc = ea.EventAccumulator(directory)
      acc.Reload()
      self.assertTagsEqual(
          acc.Tags(),
          {
              ea.GRAPH: True,
              ea.META_GRAPH: True,
          },
      )
  
      expected_graph_def = graph_pb2.GraphDef.FromString(
          graph.as_graph_def(add_shapes=True).SerializeToString()
      )
      self.assertProtoEquals(expected_graph_def, acc.Graph())
  
      expected_meta_graph = meta_graph_pb2.MetaGraphDef.FromString(
          meta_graph_def.SerializeToString()
      )
      self.assertProtoEquals(expected_meta_graph, acc.MetaGraph())
  
imports: import os
  import numpy
  import tensorflow
  from tensorboard.backend.event_processing import event_accumulator
  from tensorboard.compat.proto import config_pb2
  from tensorboard.compat.proto import event_pb2
  from tensorboard.compat.proto import graph_pb2
  from tensorboard.compat.proto import meta_graph_pb2
  from tensorboard.compat.proto import summary_pb2
  from tensorboard.plugins.distribution import compressor
  from tensorboard.util import tensor_util
  from tensorboard.util import test_util
  from tensorboard.util import tb_logging
label_desc: Use image node_id 2 for calling the RealisticEventAccumulatorTest obj's underlying member method code with example usage: obj.testGraphFromMetaGraphBecomesAvailable() without return types