code: def testGetAvailableTags(self):
      data = [
          {"tag": "c", "histo": 2, "step": 10},
          {"tag": "c", "histo": 2, "step": 11},
          {"tag": "c", "histo": 2, "step": 9},
          {"tag": "b", "simple_value": 2, "step": 20},
          {"tag": "b", "simple_value": 2, "step": 15},
          {"tag": "a", "simple_value": 2, "step": 3},
      ]
      self._WriteScalarSummaries(data)
      units = efi.get_inspection_units(self.logdir)
      tags = efi.get_unique_tags(units[0].field_to_obs)
      self.assertEqual(["a", "b"], tags["scalars"])
      self.assertEqual(["c"], tags["histograms"])
  
file_path: tensorboard/tensorboard/backend/event_processing/event_file_inspector_test.py
imports: import os
  import shutil
  import tensorflow
  from tensorboard.backend.event_processing import event_file_inspector
  from tensorboard.compat.proto import event_pb2
  from tensorboard.compat.proto import summary_pb2
  from tensorboard.util import test_util
label_desc: Use image node_id 6 for calling the EventFileInspectorTest obj's underlying member method code with example usage: obj.testGetAvailableTags() without return types