code: def test_4bit(self):
      test_file = "Tests/images/hopper_gray_4bpp.tif"
      original = hopper("L")
      with Image.open(test_file) as im:
          assert im.size == (128, 128)
          assert im.mode == "L"
          assert_image_similar(im, original, 7.3)
  
imports: import os
  from io import BytesIO
  import pytest
  from PIL import Image, ImageFile, TiffImagePlugin
  from PIL.TiffImagePlugin import RESOLUTION_UNIT, X_RESOLUTION, Y_RESOLUTION
  from .helper import assert_image_equal, assert_image_equal_tofile, assert_image_similar, assert_image_similar_tofile, hopper, is_pypy, is_win32
label_desc: Use image node_id 44 for calling the TestFileTiff obj's underlying member method code with example usage: obj.test_4bit() without return types