code: def test_regex(self):
      g = hl.Graph()
      a = hl.Node(uid="a", name="a", op="a")
      b = hl.Node(uid="b", name="b", op="b")
      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(b)
      g.add_node(c)
      g.add_node(d)
      g.add_edge(a, b)
      g.add_edge(b, c)
      g.add_edge(b, d)
  
      t = ht.Rename(op=r"a", to="bbb")
      g = t.apply(g)
      self.assertEqual(g["a"].op, "bbb")
  
      t = ht.Rename(op=r"b(.*)", to=r"x\1")
      g = t.apply(g)
      self.assertEqual(g["a"].op, "xbb")
      self.assertEqual(g["b"].op, "x")
  
imports: import unittest
  import hiddenlayer
  import hiddenlayer.ge
  import hiddenlayer.transforms
label_desc: Use image node_id 1 for calling the TestTransforms obj's underlying member method code with example usage: obj.test_regex() without return types