code: def _to_zx_transform(
      tape: QuantumTape, expand_measurements=False
  ) -> (Sequence[QuantumTape], Callable):
      """Private function to convert a PennyLane tape to a `PyZX graph <https://pyzx.readthedocs.io/en/latest/>`_ ."""
      # Avoid to make PyZX a requirement for PennyLane.
      try:
          # pylint: disable=import-outside-toplevel
          import pyzx
          from pyzx.circuit.gates import TargetMapper
          from pyzx.graph import Graph
  
      except ImportError as Error:
          raise ImportError(
              "This feature requires PyZX. It can be installed with: pip install pyzx"
          ) from Error
  
      # Dictionary of gates (PennyLane to PyZX circuit)
      gate_types = {
          "PauliX": pyzx.circuit.gates.NOT,
          "PauliZ": pyzx.circuit.gates.Z,
          "S": pyzx.circuit.gates.S,
          "T": pyzx.circuit.gates.T,
          "Hadamard": pyzx.circuit.gates.HAD,
          "RX": pyzx.circuit.gates.XPhase,
          "RZ": pyzx.circuit.gates.ZPhase,
          "PhaseShift": pyzx.circuit.gates.ZPhase,
          "SWAP": pyzx.circuit.gates.SWAP,
          "CNOT": pyzx.circuit.gates.CNOT,
          "CZ": pyzx.circuit.gates.CZ,
          "CRZ": pyzx.circuit.gates.CRZ,
          "CH": pyzx.circuit.gates.CHAD,
          "CCZ": pyzx.circuit.gates.CCZ,
          "Toffoli": pyzx.circuit.gates.Tofolli,
      }
  
      def processing_fn(res):
          # Create the graph, a qubit mapper, the classical mapper stays empty as PennyLane does not support classical bits.
          graph = Graph(None)
          q_mapper = TargetMapper()
          c_mapper = TargetMapper()
  
          # Map the wires to consecutive wires
  
          consecutive_wires = Wires(range(len(res[0].wires)))
          consecutive_wires_map = OrderedDict(
              zip(res[0].wires, consecutive_wires)
          )
          mapped_tapes, fn = qml.map_wires(
              input=res[0], wire_map=consecutive_wires_map
          )
          mapped_tape = fn(mapped_tapes)
  
          inputs = []
  
          # Create the qubits in the graph and the qubit mapper
          for i in range(len(mapped_tape.wires)):
              vertex = graph.add_vertex(VertexType.BOUNDARY, i, 0)
              inputs.append(vertex)
              q_mapper.set_prev_vertex(i, vertex)
              q_mapper.set_next_row(i, 1)
              q_mapper.set_qubit(i, i)
  
          # Expand the tape to be compatible with PyZX and add rotations first for measurements
          stop_crit = qml.BooleanFn(lambda obj: obj.name in gate_types)
          mapped_tape = qml.tape.tape.expand_tape(
              mapped_tape,
              depth=10,
              stop_at=stop_crit,
              expand_measurements=expand_measurements,
          )
  
          expanded_operations = []
  
          # Define specific decompositions
          for op in mapped_tape.operations:
              if op.name == "RY":
                  theta = op.data[0]
                  decomp = [
                      qml.RX(np.pi / 2, wires=op.wires),
                      qml.RZ(theta + np.pi, wires=op.wires),
                      qml.RX(np.pi / 2, wires=op.wires),
                      qml.RZ(3 * np.pi, wires=op.wires),
                  ]
                  expanded_operations.extend(decomp)
              else:
                  expanded_operations.append(op)
  
          expanded_tape = QuantumScript(
              expanded_operations, mapped_tape.measurements
          )
  
          _add_operations_to_graph(
              expanded_tape, graph, gate_types, q_mapper, c_mapper
          )
  
          row = max(q_mapper.max_row(), c_mapper.max_row())
  
          outputs = []
          for mapper in (q_mapper, c_mapper):
              for label in mapper.labels():
                  qubit = mapper.to_qubit(label)
                  vertex = graph.add_vertex(
                      VertexType.BOUNDARY, qubit, row
                  )
                  outputs.append(vertex)
                  pre_vertex = mapper.prev_vertex(label)
                  graph.add_edge(graph.edge(pre_vertex, vertex))
  
          graph.set_inputs(tuple(inputs))
          graph.set_outputs(tuple(outputs))
  
          return graph
  
      return [tape], processing_fn
  
file_path: pennylane/pennylane/transforms/zx/converter.py
imports: from functools import partial
  from typing import Sequence, Callable
  from collections import OrderedDict
  import numpy
  import pennylane
  from pennylane.tape import QuantumScript, QuantumTape
  from pennylane.transforms.op_transforms import OperationTransformError
  from pennylane.transforms import transform
  from pennylane.wires import Wires
label_desc: Use image node_id 2 for calling a global function with example usage: _to_zx_transform(tape, expand_measurements) and returns: list,  processing_fn, graph