code: def hf_energy(mol):
      r"""Return a function that computes the Hartree-Fock energy.
  
      Args:
          mol (~qchem.molecule.Molecule): the molecule object
  
      Returns:
          function: function that computes the Hartree-Fock energy
  
      **Example**
  
      >>> symbols  = ['H', 'H']
      >>> geometry = np.array([[0.0, 0.0, 0.0], [0.0, 0.0, 1.0]], requires_grad = False)
      >>> alpha = np.array([[3.42525091, 0.62391373, 0.1688554],
      >>>                   [3.42525091, 0.62391373, 0.1688554]], requires_grad=True)
      >>> mol = qml.qchem.Molecule(symbols, geometry, alpha=alpha)
      >>> args = [alpha]
      >>> hf_energy(mol)(*args)
      -1.065999461545263
      """
  
      def _hf_energy(*args):
          r"""Compute the Hartree-Fock energy.
  
          Args:
              *args (array[array[float]]): initial values of the differentiable parameters
  
          Returns:
              float: the Hartree-Fock energy
          """
          _, coeffs, fock_matrix, h_core, _ = scf(mol)(*args)
          e_rep = nuclear_energy(mol.nuclear_charges, mol.coordinates)(
              *args
          )
          e_elec = qml.math.einsum(
              "pq,qp",
              fock_matrix + h_core,
              mol_density_matrix(mol.n_electrons, coeffs),
          )
          energy = e_elec + e_rep
          return energy.reshape(())
  
      return _hf_energy
  
imports: import itertools
  import pennylane
  from .matrices import core_matrix, mol_density_matrix, overlap_matrix, repulsion_tensor
label_desc: Use image node_id 3 for calling a global function with example usage: hf_energy(mol) and returns: _hf_energy, energy