code: def preprocess(self, data):
      images = []
  
      for row in data:
          image = row.get("data") or row.get("body")
          if isinstance(image, str):
              image = base64.b64decode(image)
          image = mmcv.imfrombytes(image)
          images.append(image)
  
      return images
  
file_path: mmdetection/tools/deployment/mmdet_handler.py
imports: import base64
  import os
  import mmcv
  import numpy
  import torch
  from ts.torch_handler.base_handler import BaseHandler
  from mmdet.apis import inference_detector, init_detector
label_desc: Use image node_id 2 for calling the MMdetHandler obj's underlying member method code with example usage: obj.preprocess(data) and returns: images