'Synchronizes parameters from devices to CPU. This function should be called after
calling `update` that updates the parameters on the devices, before one can read the
latest parameters from ``self._arg_params`` and ``self._aux_params``.'

def _sync_params_from_devices(self):

    self._exec_group.get_params(self._arg_params, self._aux_params)
    self._params_dirty = False
