code: def test_merge_only(self):
      # Test `is_same_graph` when `equal_computations` cannot be used.
  
      x, y, z = vectors("x", "y", "z")
      t = x * y
      self.check(
          [
              (x, t, (({}, False), ({t: x}, True))),
              (
                  t * 2,
                  x * 2,
                  (
                      ({}, False),
                      ({t: x}, True),
                  ),
              ),
              (
                  x * x,
                  x * y,
                  (
                      ({}, False),
                      ({y: x}, True),
                  ),
              ),
              (
                  x * x,
                  x * y,
                  (
                      ({}, False),
                      ({y: x}, True),
                  ),
              ),
              (
                  x * x + z,
                  x * y + t,
                  (({}, False), ({y: x}, False), ({y: x, t: z}, True)),
              ),
          ],
      )
  
file_path: pytensor/tests/graph/rewriting/test_utils.py
imports: from pytensor.graph.fg import FunctionGraph
  from pytensor.graph.rewriting.basic import graph_rewriter
  from pytensor.graph.rewriting.utils import is_same_graph, rewrite_graph
  from pytensor.tensor.math import neg
  from pytensor.tensor.type import vectors
label_desc: Use image node_id 4 for calling the TestIsSameGraph obj's underlying member method code with example usage: obj.test_merge_only() without return types