class_docstr: Edge stores edge details connecting two Vertex instances.
  
  The Edge class supports serialization to a JSON data format expected by the
  client side representation.  When serializing, it generates the following
  fields:
    source_index: The source Vertex index for this Edge.
    target_index: The target Vertex index for this Edge.
    data: Arbitrary data for this Edge.
docstr: Returns a simplified dictionary representing the Vertex.
  
  Returns:
    A dictionary that can easily be serialized to JSON.
docstr_tok: ["Returns","a","simplified","dictionary","representing","the","Vertex",".","Returns",":","A","dictionary","that","can","easily","be","serialized","to","JSON","."]
code: def to_dict(self):
      """Returns a simplified dictionary representing the Vertex.
  
      Returns:
        A dictionary that can easily be serialized to JSON.
      """
      return {
          "source_index": self.source,
          "target_index": self.target,
          "data": self.data,
      }
  
file_path: tensor2tensor/tensor2tensor/insights/graph.py
label_desc: Use image node_id 2 for calling the Edge obj's underlying member method code with example usage: obj.to_dict() and returns: dict