code: def test_simple_triple_apply(self):
      def identity_fun(src, edge, dst):
          return src, edge, dst
  
      nverts = 100
      ring_graph = SGraph().add_edges(
          [Edge(i, 0) for i in range(1, nverts)]
      )
      ring_graph.vertices["id"] = ring_graph.vertices["__id"]
      ring_graph.edges["src"] = ring_graph.edges["__src_id"]
      ring_graph2 = ring_graph.triple_apply(identity_fun, ["id", "src"])
  
      self.assertSequenceEqual(
          list(ring_graph2.vertices["id"]),
          list(ring_graph2.vertices["__id"]),
      )
      self.assertSequenceEqual(
          list(ring_graph2.edges["src"]),
          list(ring_graph2.edges["__src_id"]),
      )
      for i in ring_graph.edges["__dst_id"]:
          self.assertEqual(i, 0)
  
file_path: turicreate/src/python/turicreate/test/test_graph_compute.py
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  from ..None import SGraph, Edge
  import unittest
  import time
  import pytest
  import sys
label_desc: Use image node_id 1 for calling the GraphTests obj's underlying member method code with example usage: obj.test_simple_triple_apply() and returns: src,  edge,  dst