code: def add_edge(dot, src, dst):
      if not dot.get_edge(src, dst):
          dot.add_edge(pydot.Edge(src, dst))
  
file_path: tensorflow-upstream/tensorflow/python/keras/utils/vis_utils.py
imports: import os
  import sys
  from tensorflow.python.keras.utils.io_utils import path_to_string
  from tensorflow.python.util import nest
label_desc: Use image node_id 3 for calling a global function with example usage: add_edge(dot, src, dst) without return types