code: def test_effect_noise(self):
      # Arrange
      size = (100, 100)
      sigma = 128
  
      # Act
      im = Image.effect_noise(size, sigma)
  
      # Assert
      assert im.size == (100, 100)
      assert im.mode == "L"
      p0 = im.getpixel((0, 0))
      p1 = im.getpixel((0, 1))
      p2 = im.getpixel((0, 2))
      p3 = im.getpixel((0, 3))
      p4 = im.getpixel((0, 4))
      assert_not_all_same([p0, p1, p2, p3, p4])
  
imports: import io
  import os
  import shutil
  import sys
  import tempfile
  import pytest
  from PIL import Image, ImageDraw, ImagePalette, UnidentifiedImageError
  from .helper import assert_image_equal, assert_image_equal_tofile, assert_image_similar_tofile, assert_not_all_same, hopper, is_win32, mark_if_feature_version, skip_unless_feature
label_desc: Use image node_id 31 for calling the TestImage obj's underlying member method code with example usage: obj.test_effect_noise() without return types