code: def get(self, telescope, band):
          
  
          klass = self._bpass_classes.get(telescope)
          if klass is None:
              raise NotDefinedError('bandpass data for %s not defined', telescope)
  
          bp = klass()
          bp.registry = self
          bp.telescope = telescope
          bp.band = band
          return bp
docs: Get a Bandpass object for a known telescope and filter.