code: def test_test_descartes(self):
      self.assertEqual([[1]], descartes([[1]], 9))
      self.assertEqual([[1, 2]], descartes([[1], [2]], 9))
  
      num = 100
      test_list = [
          random.sample(list(range(int(1e6))), random.randint(1, 1000))
          for i in range(num)
      ]
  
      n = random.randint(10, 100)
      descartes_list = descartes(test_list, n)
  
      for item in descartes_list:
          for i in range(len(item)):
              self.assertTrue(item[i] in test_list[i])
  
      self.assertEqual(n, len(descartes_list))
  
      for i in range(len(descartes_list)):
          for j in range(i + 1, len(descartes_list)):
              self.assertTrue(descartes_list[i] != descartes_list[j])
  
imports: import unittest
  from textflint.common.utils.list_op import *
label_desc: Use image node_id 11 for calling the TestListOp obj's underlying member method code with example usage: obj.test_test_descartes() without return types