code: def test_fold_duplicates(self):
      g = hl.Graph()
      a = hl.Node(uid="a", name="a", op="a")
      b1 = hl.Node(uid="b1", name="b1", op="b", output_shape=(3, 3))
      b2 = hl.Node(uid="b2", name="b2", op="b", output_shape=(4, 4))
      c = hl.Node(uid="c", name="c", op="c")
      d = hl.Node(uid="d", name="d", op="d")
      g.add_node(a)
      g.add_node(b1)
      g.add_node(b2)
      g.add_node(c)
      g.add_node(d)
      g.add_edge(a, b1)
      g.add_edge(b1, b2)
      g.add_edge(b2, c)
      g.add_edge(b2, d)
  
      t = ht.FoldDuplicates()
      g = t.apply(g)
      self.assertEqual(g.incoming(g["c"])[0].op, "b")
      self.assertEqual(g.incoming(g["c"])[0].name, "b1")
      self.assertEqual(g.incoming(g["c"])[0].output_shape, (4, 4))
  
imports: import unittest
  import hiddenlayer
  import hiddenlayer.ge
  import hiddenlayer.transforms
label_desc: Use image node_id 3 for calling the TestTransforms obj's underlying member method code with example usage: obj.test_fold_duplicates() without return types