class_docstr: Convert between text-label and text-index 
code: def __call__(self, preds, label=None, *args, **kwargs):
      pred_relations = preds["pred_relations"]
      if isinstance(preds["pred_relations"], paddle.Tensor):
          pred_relations = pred_relations.numpy()
      pred_relations = self.decode_pred(pred_relations)
  
      if label is not None:
          return self._metric(pred_relations, label)
      else:
          return self._infer(pred_relations, *args, **kwargs)
  
file_path: PaddleOCR/ppocr/postprocess/vqa_token_re_layoutlm_postprocess.py
imports: import paddle
label_desc: Use image node_id 2 for calling the VQAReTokenLayoutLMPostProcess obj's underlying member method code with example usage: obj.__call__(preds, label) and returns: self, self