docs: def sis_metadata(self):
          """Return Olympus SIS metadata from SIS and INI tags as dict."""
          if not self.is_sis:
              return None
          tags = self.pages[0].tags
          result = {}
          try:
              result.update(tags['OlympusINI'].value)
          except Exception:
              pass
          try:
              result.update(tags['OlympusSIS'].value)
          except Exception:
              pass
          return result