code: def __call__(self, data):
      if isinstance(data["img"], str):
          data["img"] = cv2.imread(data["img"])
      for key in data.get("gt_fields", []):
          if isinstance(data[key], str):
              data[key] = cv2.imread(data[key], cv2.IMREAD_UNCHANGED)
          # if alpha and trimap has 3 channels, extract one.
          if key in ["alpha", "trimap"]:
              if len(data[key].shape) > 2:
                  data[key] = data[key][:, :, 0]
  
      if self.to_rgb:
          data["img"] = cv2.cvtColor(data["img"], cv2.COLOR_BGR2RGB)
          for key in data.get("gt_fields", []):
              if len(data[key].shape) == 2:
                  continue
              data[key] = cv2.cvtColor(data[key], cv2.COLOR_BGR2RGB)
  
      return data
  
imports: import os
  import random
  import string
  import cv2
  import numpy
  from paddleseg.transforms import functional
  from paddleseg.cvlibs import manager
  from paddleseg.utils import seg_env
  from PIL import Image
label_desc: Use image node_id 2 for calling the LoadImages obj's underlying member method code with example usage: obj.__call__(data) and returns: data