code: def test_image_mask_RGBa(self, mode):
      im = Image.new(mode, (200, 200), "white")
      im2 = getattr(self, "gradient_" + mode)
  
      self.assert_9points_paste(
          im,
          im2,
          self.gradient_RGBa,
          [
              (128, 255, 126, 255),
              (0, 127, 126, 255),
              (126, 253, 126, 255),
              (128, 127, 254, 255),
              (0, 255, 254, 255),
              (126, 125, 254, 255),
              (128, 1, 128, 255),
              (0, 129, 128, 255),
              (126, 255, 128, 255),
          ],
      )
  
imports: from __future__ import annotations
  import pytest
  from PIL import Image
  from .helper import CachedProperty, assert_image_equal
label_desc: Use image node_id 15 for calling the TestImagingPaste obj's underlying member method code with example usage: obj.test_image_mask_RGBa(mode) without return types