class_docstr: Test the qml.QSVT template.
class_docstr_tok: ["Test","the","qml.QSVT","template","."]
code: def test_flatten_unflatten(self):
      projectors = [
          qml.PCPhase(0.2, dim=1, wires=0),
          qml.PCPhase(0.3, dim=1, wires=0),
      ]
      op = qml.QSVT(qml.PauliX(wires=0), projectors)
      data, metadata = op._flatten()
      assert qml.equal(data[0], qml.PauliX(0))
      assert len(data[1]) == len(projectors)
      assert all(
          qml.equal(op1, op2) for op1, op2 in zip(data[1], projectors)
      )
  
      assert metadata == tuple()
  
      new_op = type(op)._unflatten(*op._flatten())
      assert qml.equal(op, new_op)
      assert op is not new_op
  
imports: import pytest
  import pennylane
  from pennylane import numpy
label_desc: Use image node_id 1 for calling the TestQSVT obj's underlying member method code with example usage: obj.test_flatten_unflatten() without return types