code: def save_result(
      alpha, path, im_path, trimap=None, fg_estimate=True, fg=None
  ):
      """
      Save alpha and rgba.
  
      Args:
          alpha (numpy.ndarray): The value of alpha should in [0, 255], shape should be [h,w].
          path (str): The save path
          im_path (str): The original image path.
          trimap (str, optional): The trimap if provided. Default: None.
          fg_estimate (bool, optional): Whether to estimate the foreground, Default: True.
          fg (numpy.ndarray, optional): The foreground, if provided, fg_estimate is invalid. Default: None.
      """
      dirname = os.path.dirname(path)
      if not os.path.exists(dirname):
          os.makedirs(dirname)
      basename = os.path.basename(path)
      name = os.path.splitext(basename)[0]
      alpha_save_path = os.path.join(dirname, name + "_alpha.png")
      rgba_save_path = os.path.join(dirname, name + "_rgba.png")
  
      # save alpha matte
      if trimap is not None:
          trimap = cv2.imread(trimap, 0)
          alpha[trimap == 0] = 0
          alpha[trimap == 255] = 255
      alpha = (alpha).astype("uint8")
      cv2.imwrite(alpha_save_path, alpha)
  
      # save rgba
      im = cv2.imread(im_path)
      if fg is None:
          if fg_estimate:
              fg = (
                  estimate_foreground_ml(im / 255.0, alpha / 255.0)
                  * 255
              )
          else:
              fg = im
      fg = fg.astype("uint8")
      alpha = alpha[:, :, np.newaxis]
      rgba = np.concatenate((fg, alpha), axis=-1)
      cv2.imwrite(rgba_save_path, rgba)
  
      return fg
  
file_path: PaddleSeg/Matting/ppmatting/core/predict.py
imports: import os
  import math
  import time
  import cv2
  import numpy
  import paddle
  import paddle.nn.functional
  from paddleseg import utils
  from paddleseg.core import infer
  from paddleseg.utils import logger, progbar, TimeAverager
  from ppmatting.utils import mkdir, estimate_foreground_ml
label_desc: Use image node_id 2 for calling a global function with example usage: save_result(alpha, path, im_path, trimap, fg_estimate, fg) and returns: fg