code: def matrix(self, wire_order=None):
      return np.eye(2**self.num_wires)
  
imports: from copy import copy
  import numpy
  import pytest
  import pennylane
  from pennylane.operation import DecompositionUndefinedError
  from pennylane.ops.op_math import CompositeOp, Prod, Sum, SProd
  from pennylane.wires import Wires
label_desc: Use image node_id 3 for calling the ValidOp obj's underlying member method code with example usage: obj.matrix(wire_order) and returns: np