code: def test_generate_random_mask(self):
      mask = pic.generate_random_mask(
          image_height=100, image_width=100, fraction=0.2
      )
      self.assertEqual(np.count_nonzero(mask), 2000)
  
file_path: saliency/saliency/metrics/pic_test.py
imports: import numpy
  import os
  import unittest
  from .None import pic
  from pathlib import Path
  from PIL import Image
label_desc: Use image node_id 7 for calling the PicTest obj's underlying member method code with example usage: obj.test_generate_random_mask() without return types