code: def Posterize(img, v):
      """
      Applies PIL.ImageOps.posterize to the image
      """
      assert 4 <= v <= 8, f"{v} out of range [4, 8]"
      v = int(v)
      return PIL.ImageOps.posterize(img, v)
  
imports: import numpy
  import PIL
label_desc: Use image node_id 3 for calling a global function with example usage: Posterize(img, v) and returns: PIL