🐛 fix error msg

    if node_pos_features is not None:

      if isinstance(node_pos_features, np.ndarray) is False:

        raise ValueError('pos must be np.ndarray or None.')

        raise ValueError('node_pos_features must be np.ndarray or None.')

      elif node_pos_features.shape[0] != node_features.shape[0]:

        raise ValueError('The length of pos must be the same as the \

        raise ValueError(

            'The length of node_pos_features must be the same as the \

                          length of node_features.')

    self.node_features = node_features