docstr: Tests whether histograms are inserted into EventAccumulator.
code: def testHistograms(self):
      """Tests whether histograms are inserted into EventAccumulator."""
      gen = _EventGenerator(self)
      acc = ea.EventAccumulator(gen)
  
      val1 = ea.HistogramValue(
          min=1,
          max=2,
          num=3,
          sum=4,
          sum_squares=5,
          bucket_limit=[1, 2, 3],
          bucket=[0, 3, 0],
      )
      val2 = ea.HistogramValue(
          min=-2,
          max=3,
          num=4,
          sum=5,
          sum_squares=6,
          bucket_limit=[2, 3, 4],
          bucket=[1, 3, 0],
      )
  
      hst1 = ea.HistogramEvent(
          wall_time=1, step=10, histogram_value=val1
      )
      hst2 = ea.HistogramEvent(
          wall_time=2, step=12, histogram_value=val2
      )
      gen.AddHistogram(
          "hst1",
          wall_time=1,
          step=10,
          hmin=1,
          hmax=2,
          hnum=3,
          hsum=4,
          hsum_squares=5,
          hbucket_limit=[1, 2, 3],
          hbucket=[0, 3, 0],
      )
      gen.AddHistogram(
          "hst2",
          wall_time=2,
          step=12,
          hmin=-2,
          hmax=3,
          hnum=4,
          hsum=5,
          hsum_squares=6,
          hbucket_limit=[2, 3, 4],
          hbucket=[1, 3, 0],
      )
      acc.Reload()
      self.assertEqual(acc.Histograms("hst1"), [hst1])
      self.assertEqual(acc.Histograms("hst2"), [hst2])
  
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 7 for calling the MockingEventAccumulatorTest obj's underlying member method code with example usage: obj.testHistograms() without return types