code: def build_sdist(sdist_directory, config_settings):
      
      backend = _build_backend()
      try:
          return backend.build_sdist(sdist_directory, config_settings)
      except getattr(backend, 'UnsupportedOperation', _DummyException):
          raise GotUnsupportedOperation(traceback.format_exc())
docs: Invoke the mandatory build_sdist hook.