code: def test_save_stdout(self, buffer):
      old_stdout = sys.stdout
  
      if buffer:
  
          class MyStdOut:
              buffer = BytesIO()
  
          mystdout = MyStdOut()
      else:
          mystdout = BytesIO()
  
      sys.stdout = mystdout
  
      with Image.open(TEST_PNG_FILE) as im:
          im.save(sys.stdout, "PNG")
  
      # Reset stdout
      sys.stdout = old_stdout
  
      if buffer:
          mystdout = mystdout.buffer
      with Image.open(mystdout) as reloaded:
          assert_image_equal_tofile(reloaded, TEST_PNG_FILE)
  
imports: import re
  import sys
  import zlib
  from io import BytesIO
  import pytest
  from PIL import Image, ImageFile, PngImagePlugin, features
  from .helper import PillowLeakTestCase, assert_image, assert_image_equal, assert_image_equal_tofile, hopper, is_win32, mark_if_feature_version, skip_unless_feature
label_desc: Use image node_id 51 for calling the TestFilePng obj's underlying member method code with example usage: obj.test_save_stdout(buffer) without return types