code: def stereo_bm_preset(self, value):
          
          if value in (cv2.STEREO_BM_BASIC_PRESET,
                       cv2.STEREO_BM_FISH_EYE_PRESET,
                       cv2.STEREO_BM_NARROW_PRESET):
              self._bm_preset = value
          else:
              raise InvalidBMPresetError("Stereo BM preset must be defined as "
                                         "cv2.STEREO_BM_*_PRESET.")
          self._replace_bm()
docs: Set private ``_stereo_bm_preset`` and reset ``_block_matcher``.