code: def _get_arrays(self, wavelengths, **kwargs):
          
          x = self._validate_wavelengths(wavelengths)
          y = self(x, **kwargs)
  
          if isinstance(wavelengths, u.Quantity):
              w = x.to(wavelengths.unit, u.spectral())
          else:
              w = x
  
          return w, y
docs: Get sampled spectrum or bandpass in user units.