code: def _publish_rendered_dot_graph_file_from_leaf_nodes(
      self, leaf_nodes
  ):
      dot_string = nodes.get_dot_graph(leaf_nodes).to_string()
      tf.io.gfile.makedirs(self.base_test_dir)
      output_file = os.path.join(
          self.base_test_dir,
          "rendered_graph_{}.svg".format(self._get_running_index()),
      )
      self.WriteRenderedDotFile(dot_string, output_file=output_file)
      return dot_string
  
imports: import functools
  import os
  import struct
  from typing import Callable, Mapping, List
  import uuid
  import apache_beam
  from apache_beam.testing import util
  import numpy
  import tensorflow
  import tensorflow_transform
  from tensorflow_transform import analyzer_nodes
  from tensorflow_transform import common_types
  from tensorflow_transform import impl_helper
  from tensorflow_transform import nodes
  import tensorflow_transform.beam
  from tensorflow_transform.beam import analysis_graph_builder
  from tensorflow_transform.beam import analyzer_cache
  from tensorflow_transform.beam import tft_unit
  from tensorflow_transform.tf_metadata import dataset_metadata
  from tfx_bsl.types import tfx_namedtuple
label_desc: Use image node_id 4 for calling the CachedImplTest obj's underlying member method code with example usage: obj._publish_rendered_dot_graph_file_from_leaf_nodes(leaf_nodes) and returns: dot_string