code: def _proc_asym_top(self):
          
          self._check_R2_axes_asym()
          if len(self.rot_sym) == 0:
              logger.debug("No rotation symmetries detected.")
              self._proc_no_rot_sym()
          elif len(self.rot_sym) == 3:
              logger.debug("Dihedral group detected.")
              self._proc_dihedral()
          else:
              logger.debug("Cyclic group detected.")
              self._proc_cyclic()
docs: Handles assymetric top molecules, which cannot contain rotational
          symmetry larger than 2.