code: def test_should_generate_run_hash_twelve_char_long(self):
      # arrange
      hash_length = 12
      expected_hash_len = 12
  
      # act
      actual_hash = utils.generate_run_hash(hash_length)
  
      # assert
      self.assertIsInstance(actual_hash, str)
      self.assertEqual(expected_hash_len, len(actual_hash))
  
imports: import unittest
  import os
  from unittest import mock
  from unittest.mock import MagicMock
  import aim.sdk.utils
label_desc: Use image node_id 5 for calling the TestUtils obj's underlying member method code with example usage: obj.test_should_generate_run_hash_twelve_char_long() without return types