class_docstr: pennylane.Identity(wires)
  The identity observable :math:`\I`.
  
  The expectation of this observable
  
  .. math::
      E[\I] = \text{Tr}(\I \rho)
  
  Args:
      wires (Iterable[Any] or Any): Wire label(s) that the identity acts on.
      id (str): custom label given to an operator instance,
          can be useful for some applications where the instance has to be identified.
  
  Corresponds to the trace of the quantum state, which in exact
  simulators should always be equal to 1.
class_docstr_tok: ["pennylane.Identity","(","wires",")","The","identity","observable",":","math",":","`","\\I","`",".","The","expectation","of","this","observable","..","math",":",":","E","[","\\I","]","=","\\text","{","Tr","}","(","\\I","\\rho",")","Args",":","wires","(","Iterable","[","Any","]","or","Any",")",":","Wire","label","(","s",")","that","the","identity","acts","on",".","id","(","str",")",":","custom","label","given","to","an","operator","instance",",","can","be","useful","for","some","applications","where","the","instance","has","to","be","identified",".","Corresponds","to","the","trace","of","the","quantum","state",",","which","in","exact","simulators","should","always","be","equal","to","1","."]
code: def _heisenberg_rep(p):
      return qml.math.array([1, 0, 0])
  
imports: from functools import lru_cache
  from scipy import sparse
  import pennylane
  from pennylane.operation import AnyWires, AllWires, CVObservable, Operation
label_desc: Use image node_id 7 for calling the Identity obj's underlying member method code with example usage: obj._heisenberg_rep(p) and returns: qml