docs: def display(self, display_before=False):
          """shows the effect of this filter"""
          try:
              copy = self.image.copy()
          except AttributeError:
              raise Exception("You need to set the Filter.image attribute for displaying")
          copy = BrightnessProcessor(brightness=0.6).process(copy)
          s, g = self._input, self.good_segments_indexes
          draw_segments(copy, s[g], (0, 255, 0))
          draw_segments(copy, s[True ^ g], (0, 0, 255))
          show_image_and_wait_for_key(copy, "segments filtered by " + self.__class__.__name__)