code: def decompose(
      hf_file, mapping="jordan_wigner", core=None, active=None
  ):
      r"""Decomposes the molecular Hamiltonian into a linear combination of Pauli operators using
      OpenFermion tools.
  
      This function uses OpenFermion functions to build the second-quantized electronic Hamiltonian
      of the molecule and map it to the Pauli basis using the Jordan-Wigner or Bravyi-Kitaev
      transformation.
  
      Args:
          hf_file (str): absolute path to the hdf5-formatted file with the
              Hartree-Fock electronic structure
          mapping (str): Specifies the transformation to map the fermionic Hamiltonian to the
              Pauli basis. Input values can be ``'jordan_wigner'`` or ``'bravyi_kitaev'``.
          core (list): indices of core orbitals, i.e., the orbitals that are
              not correlated in the many-body wave function
          active (list): indices of active orbitals, i.e., the orbitals used to
              build the correlated many-body wave function
  
      Returns:
          QubitOperator: an instance of OpenFermion's ``QubitOperator``
  
      **Example**
  
      >>> decompose('./pyscf/sto-3g/h2', mapping='bravyi_kitaev')
      (-0.04207897696293986+0j) [] + (0.04475014401986122+0j) [X0 Z1 X2] +
      (0.04475014401986122+0j) [X0 Z1 X2 Z3] +(0.04475014401986122+0j) [Y0 Z1 Y2] +
      (0.04475014401986122+0j) [Y0 Z1 Y2 Z3] +(0.17771287459806262+0j) [Z0] +
      (0.17771287459806265+0j) [Z0 Z1] +(0.1676831945625423+0j) [Z0 Z1 Z2] +
      (0.1676831945625423+0j) [Z0 Z1 Z2 Z3] +(0.12293305054268105+0j) [Z0 Z2] +
      (0.12293305054268105+0j) [Z0 Z2 Z3] +(0.1705973832722409+0j) [Z1] +
      (-0.2427428049645989+0j) [Z1 Z2 Z3] +(0.1762764080276107+0j) [Z1 Z3] +
      (-0.2427428049645989+0j) [Z2]
      """
      openfermion, _ = _import_of()
  
      # loading HF data from the hdf5 file
      molecule = openfermion.MolecularData(filename=hf_file.strip())
  
      # getting the terms entering the second-quantized Hamiltonian
      terms_molecular_hamiltonian = molecule.get_molecular_hamiltonian(
          occupied_indices=core, active_indices=active
      )
  
      # generating the fermionic Hamiltonian
      fermionic_hamiltonian = (
          openfermion.transforms.get_fermion_operator(
              terms_molecular_hamiltonian
          )
      )
  
      mapping = mapping.strip().lower()
  
      if mapping not in ("jordan_wigner", "bravyi_kitaev"):
          raise TypeError(
              f"The '{mapping}' transformation is not available. \n "
              f"Please set 'mapping' to 'jordan_wigner' or 'bravyi_kitaev'."
          )
  
      # fermionic-to-qubit transformation of the Hamiltonian
      if mapping == "bravyi_kitaev":
          return openfermion.transforms.bravyi_kitaev(
              fermionic_hamiltonian
          )
  
      return openfermion.transforms.jordan_wigner(fermionic_hamiltonian)
  
file_path: pennylane/pennylane/qchem/openfermion_obs.py
imports: import os
  import numpy
  import pennylane
  from pennylane.operation import active_new_opmath
label_desc: Use image node_id 7 for calling a global function with example usage: decompose(hf_file, mapping, core, active) and returns: openfermion, openfermion