def _proc_asym_top(self):
        """
        Handles assymetric top molecules, which cannot contain rotational
        symmetry larger than 2.
        """
        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()
Handles assymetric top molecules, which cannot contain rotational
        symmetry larger than 2.