code: def test_image_mask_L(self, mode):
      im = Image.new(mode, (200, 200), "white")
      im2 = getattr(self, "gradient_" + mode)
  
      self.assert_9points_paste(
          im,
          im2,
          self.mask_L,
          [
              (128, 191, 255, 191),
              (208, 239, 239, 208),
              (255, 255, 255, 255),
              (112, 111, 206, 207),
              (192, 191, 191, 191),
              (239, 239, 207, 207),
              (128, 1, 128, 254),
              (207, 113, 112, 207),
              (255, 191, 128, 191),
          ],
      )
  
imports: from __future__ import annotations
  import pytest
  from PIL import Image
  from .helper import CachedProperty, assert_image_equal
label_desc: Use image node_id 12 for calling the TestImagingPaste obj's underlying member method code with example usage: obj.test_image_mask_L(mode) without return types