code: def original_failure(self):
          
          try:
              result = self._result(0.0)
          except TimeoutError:
              return None
          if isinstance(result, Failure):
              return result
          else:
              return None
docs: Return the underlying Failure object, if the result is an error.
  
          If no result is yet available, or the result was not an error, None is
          returned.
  
          This method is useful if you want to get the original traceback for an
          error result.