Return all tags found in the value stream.

    Returns:
      A `{tagType: ['list', 'of', 'tags']}` dictionary.

def Tags(self):
    """Return all tags found in the value stream.

    Returns:
      A `{tagType: ['list', 'of', 'tags']}` dictionary.
    """
    return {
        IMAGES: self.images.Keys(),
        AUDIO: self.audios.Keys(),
        HISTOGRAMS: self.histograms.Keys(),
        SCALARS: self.scalars.Keys(),
        COMPRESSED_HISTOGRAMS: self.compressed_histograms.Keys(),
        TENSORS: self.tensors.Keys(),
        # Use a heuristic: if the metagraph is available, but
        # graph is not, then we assume the metagraph contains the graph.
        GRAPH: self._graph is not None,
        META_GRAPH: self._meta_graph is not None,
        RUN_METADATA: list(self._tagged_metadata.keys())
    }