class_docstr: Convert between text-label and text-index 
class_docstr_tok: ["Convert","between","text-label","and","text-index"]
code: def __call__(self, preds, batch=None, *args, **kwargs):
      if isinstance(preds, tuple):
          preds = preds[0]
      if isinstance(preds, paddle.Tensor):
          preds = preds.numpy()
  
      if batch is not None:
          return self._metric(preds, batch[5])
      else:
          return self._infer(preds, **kwargs)
  
file_path: PaddleOCR/ppocr/postprocess/vqa_token_ser_layoutlm_postprocess.py
imports: import numpy
  import paddle
  from ppocr.utils.utility import load_vqa_bio_label_maps
label_desc: Use image node_id 2 for calling the VQASerTokenLayoutLMPostProcess obj's underlying member method code with example usage: obj.__call__(preds, batch) and returns: self, self