code: def close(self):
          
          if self._Q is not None:
              for T in self._T:
                  self._Q.interrupt()
              for n, T in enumerate(self._T):
                  _log.debug('Join Context worker %d', n)
                  T.join()
              _log.debug('Joined Context workers')
              self._Q, self._T = None, None
          super(Context, self).close()
docs: Force close all Channels and cancel all Operations