class_docstr: Convert between text-label and text-index 
class_docstr_tok: ["Convert","between","text-label","and","text-index"]
code: def _metric(self, preds, label):
      pred_idxs = preds.argmax(axis=2)
      decode_out_list = [[] for _ in range(pred_idxs.shape[0])]
      label_decode_out_list = [[] for _ in range(pred_idxs.shape[0])]
  
      for i in range(pred_idxs.shape[0]):
          for j in range(pred_idxs.shape[1]):
              if label[i, j] != -100:
                  label_decode_out_list[i].append(
                      self.id2label_map[label[i, j]]
                  )
                  decode_out_list[i].append(
                      self.id2label_map[pred_idxs[i, j]]
                  )
      return decode_out_list, label_decode_out_list
  
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 3 for calling the VQASerTokenLayoutLMPostProcess obj's underlying member method code with example usage: obj._metric(preds, label) and returns: decode_out_list,  label_decode_out_list