code: def pauli_word_to_matrix(pauli_word, wire_map=None):
      """Convert a Pauli word from a tensor to its matrix representation.
  
      The matrix representation of a Pauli word has dimension :math:`2^n \\times 2^n`,
      where :math:`n` is the number of qubits provided in ``wire_map``. For wires
      that the Pauli word does not act on, identities must be inserted into the tensor
      product at the correct positions.
  
      Args:
          pauli_word (Observable): an observable, either a :class:`~.Tensor` instance or
              single-qubit observable representing a Pauli group element.
          wire_map (dict[Union[str, int], int]): dictionary containing all wire labels used in
              the Pauli word as keys, and unique integer labels as their values
  
      Returns:
          array[complex]: The matrix representation of the multi-qubit Pauli over the
          specified wire map.
  
      Raises:
          TypeError: if the input observable is not a proper Pauli word.
  
      **Example**
  
      >>> wire_map = {'a' : 0, 'b' : 1}
      >>> pauli_word = qml.PauliX('a') @ qml.PauliY('b')
      >>> pauli_word_to_matrix(pauli_word, wire_map=wire_map)
      array([[0.+0.j, 0.-0.j, 0.+0.j, 0.-1.j],
             [0.+0.j, 0.+0.j, 0.+1.j, 0.+0.j],
             [0.+0.j, 0.-1.j, 0.+0.j, 0.-0.j],
             [0.+1.j, 0.+0.j, 0.+0.j, 0.+0.j]])
      """
      if not is_pauli_word(pauli_word):
          raise TypeError(
              f"Expected Pauli word observables, instead got {pauli_word}"
          )
  
      # If there is no wire map, we must infer from the structure of Paulis
      if wire_map is None:
          wire_map = {
              pauli_word.wires.labels[i]: i
              for i in range(len(pauli_word.wires))
          }
  
      n_qubits = len(wire_map)
  
      # If there is only a single qubit, we can return the matrix directly
      if n_qubits == 1:
          return pauli_word.matrix()
  
      # There may be more than one qubit in the Pauli but still only
      # one of them with anything acting on it, so take that into account
      pauli_names = (
          [pauli_word.name]
          if isinstance(pauli_word.name, str)
          else pauli_word.name
      )
  
      # Special case: the identity Pauli
      if pauli_names == ["Identity"]:
          return np.eye(2**n_qubits)
  
      # If there is more than one qubit, we must go through the wire map wire
      # by wire and pick out the relevant matrices
      pauli_mats = [ID_MAT for x in range(n_qubits)]
  
      for wire_label, wire_idx in wire_map.items():
          if wire_label in pauli_word.wires.labels:
              op_idx = pauli_word.wires.labels.index(wire_label)
              # compute_matrix() only works because we work with Paulis here
              pauli_mats[wire_idx] = getattr(
                  qml, pauli_names[op_idx]
              ).compute_matrix()
  
      return reduce(np.kron, pauli_mats)
  
imports: from functools import lru_cache, reduce, singledispatch
  from itertools import product
  from typing import List, Union
  from warnings import warn
  import numpy
  import pennylane
  from pennylane.operation import Tensor
  from pennylane.ops import Hamiltonian, Identity, PauliX, PauliY, PauliZ, Prod, SProd
  from pennylane.tape import OperationRecorder
  from pennylane.wires import Wires
label_desc: Use image node_id 14 for calling a global function with example usage: pauli_word_to_matrix(pauli_word, wire_map) and returns: reduce, pauli_word, np