code: def add_edge(dot, src, dst):
      if not dot.get_edge(src, dst):
          edge = pydot.Edge(src, dst)
          edge.set("penwidth", "2")
          dot.add_edge(edge)
  
file_path: keras/keras/utils/model_visualization.py
imports: import os
  import sys
  from keras.api_export import keras_export
  from keras.utils import io_utils
label_desc: Use image node_id 3 for calling a global function with example usage: add_edge(dot, src, dst) without return types