code: def wait(self):
          
          e, r = self.result.get()
          self.slave.join()
          self.slave = None
          self.result = None
          if isinstance(e, Exception):
              raise SlaveException(e, r)
          return r
docs: Wait and join the child process. 
              The return value of the function call is returned.
              If any exception occurred it is wrapped and raised.