code: def get_unique_tags(field_to_obs):
      """Returns a dictionary of tags that a user could query over.
  
      Args:
        field_to_obs: Dict that maps string field to `Observation` list.
  
      Returns:
        A dict that maps keys in `TAG_FIELDS` to a list of string tags present in
        the event files. If the dict does not have any observations of the type,
        maps to an empty list so that we can render this to console.
      """
      return {
          field: sorted(set([x.get("tag", "") for x in observations]))
          for field, observations in field_to_obs.items()
          if field in TAG_FIELDS
      }
  
file_path: tensorboard/tensorboard/backend/event_processing/event_file_inspector.py
imports: import dataclasses
  import itertools
  import os
  from typing import Any, Generator, Mapping
  from tensorboard.backend.event_processing import event_accumulator
  from tensorboard.backend.event_processing import event_file_loader
  from tensorboard.backend.event_processing import io_wrapper
  from tensorboard.compat import tf
  from tensorboard.compat.proto import event_pb2
label_desc: Use image node_id 2 for calling a global function with example usage: get_unique_tags(field_to_obs) and returns: unknown