code: def test_subsets_v2(self):
      nums1 = [1, 2, 3]
      answer1 = [[1, 2, 3], [1, 2], [1, 3], [1], [2, 3], [2], [3], []]
      self.assertEqual(sorted(subsets_v2(nums1)), sorted(answer1))
  
      nums2 = [1, 2, 3, 4]
      answer2 = [
          [1, 2, 3, 4],
          [1, 2, 3],
          [1, 2, 4],
          [1, 2],
          [1, 3, 4],
          [1, 3],
          [1, 4],
          [1],
          [2, 3, 4],
          [2, 3],
          [2, 4],
          [2],
          [3, 4],
          [3],
          [4],
          [],
      ]
      self.assertEqual(sorted(subsets_v2(nums2)), sorted(answer2))
  
imports: from algorithms.backtrack import add_operators, permute_iter, anagram, array_sum_combinations, unique_array_sum_combinations, combination_sum, get_factors, recursive_get_factors, find_words, generate_abbreviations, generate_parenthesis_v1, generate_parenthesis_v2, letter_combinations, palindromic_substrings, pattern_match, permute_unique, permute, permute_recursive, subsets_unique, subsets, subsets_v2
  import unittest
label_desc: Use image node_id 2 for calling the TestSubsets obj's underlying member method code with example usage: obj.test_subsets_v2() without return types