code: def load_rdkit_mol(cls, mol):
          
          obj = cls()
          obj.system = obj._Input.load_rdkit_mol(mol)
          return obj
docs: Create a :class:`MolecularSystem` from :class:`rdkit.Chem.rdchem.Mol`.
  
          Parameters
          ----------
          mol : :class:`rdkit.Chem.rdchem.Mol`
             An RDKit molecule object.
  
          Returns
          -------
          :class:`pywindow.molecular.MolecularSystem`
              :class:`MolecularSystem`