docs: def _to_bytes(self, data):
          """
          Normalize a text data to bytes (type `bytes`) so that the go bindings can
          handle it easily.
          """
          # TODO: On Python 3, move this `if` line to the `except` branch
          # as the common case will indeed no longer be bytes.
          if not isinstance(data, bytes):
              try:
                  return data.encode('utf-8')
              except Exception:
                  return None
  
          return data