def validate_units(self):
        """Ensure that wavelenth and flux units belong to the
        correct classes.

        Raises
        ------
        TypeError
            Wavelength unit is not `~pysynphot.units.WaveUnits` or
            flux unit is not `~pysynphot.units.FluxUnits`.

        """
        if (not isinstance(self.waveunits, units.WaveUnits)):
            raise TypeError("%s is not a valid WaveUnit" % self.waveunits)
        if (not isinstance(self.fluxunits, units.FluxUnits)):
            raise TypeError("%s is not a valid FluxUnit" % self.fluxunits)
Ensure that wavelenth and flux units belong to the
        correct classes.

        Raises
        ------
        TypeError
            Wavelength unit is not `~pysynphot.units.WaveUnits` or
            flux unit is not `~pysynphot.units.FluxUnits`.