code: def test_color_solid(self, mode):
      im = Image.new(mode, (200, 200), "black")
  
      rect = (12, 23, 128 + 12, 128 + 23)
      im.paste("white", rect)
  
      hist = im.crop(rect).histogram()
      while hist:
          head, hist = hist[:256], hist[256:]
          assert head[255] == 128 * 128
          assert sum(head[:255]) == 0
  
imports: from __future__ import annotations
  import pytest
  from PIL import Image
  from .helper import CachedProperty, assert_image_equal
label_desc: Use image node_id 16 for calling the TestImagingPaste obj's underlying member method code with example usage: obj.test_color_solid(mode) without return types