code: def test_plte_length(self, tmp_path):
      im = Image.new("P", (1, 1))
      im.putpalette((1, 1, 1))
  
      out = str(tmp_path / "temp.png")
      im.save(str(tmp_path / "temp.png"))
  
      with Image.open(out) as reloaded:
          assert len(reloaded.png.im_palette[1]) == 3
  
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 43 for calling the TestFilePng obj's underlying member method code with example usage: obj.test_plte_length(tmp_path) without return types