code: def test_flatten_unflatten():
      """Tests the flatten and unflatten methods for GroverOperator."""
      work_wires = qml.wires.Wires((3, 4))
      op = qml.GroverOperator(wires=(0, 1, 2), work_wires=work_wires)
      data, metadata = op._flatten()
      assert data == tuple()
      assert len(metadata) == 2
      assert metadata[0] == op.wires
      assert metadata[1] == (("work_wires", work_wires),)
  
      # make sure metadata hashable
      assert hash(metadata)
  
      new_op = type(op)._unflatten(*op._flatten())
      assert qml.equal(op, new_op)
      assert new_op is not op
  
file_path: pennylane/tests/templates/test_subroutines/test_grover.py
imports: import functools
  import itertools
  import pytest
  import numpy
  import pennylane
  from pennylane.ops import Hadamard, PauliZ, MultiControlledX
label_desc: Use image node_id 2 for calling a global function with example usage: test_flatten_unflatten() without return types