code: def test_set_legacy_api(self):
      ifd = TiffImagePlugin.ImageFileDirectory_v2()
      with pytest.raises(Exception) as e:
          ifd.legacy_api = None
      assert str(e.value) == "Not allowing setting of legacy api"
  
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 7 for calling the TestFileTiff obj's underlying member method code with example usage: obj.test_set_legacy_api() without return types