code: def test_arm_name_to_sort_key(self) -> None:
      arm_names = ["0_0", "1_10", "1_2", "10_0", "control"]
      sorted_names = sorted(
          arm_names, key=arm_name_to_sort_key, reverse=True
      )
      expected = ["control", "0_0", "1_2", "1_10", "10_0"]
      self.assertEqual(sorted_names, expected)
  
      arm_names = ["0_0", "0", "1_10", "3_2_x", "3_x", "1_2", "control"]
      sorted_names = sorted(
          arm_names, key=arm_name_to_sort_key, reverse=True
      )
      expected = ["control", "3_x", "3_2_x", "0", "0_0", "1_2", "1_10"]
      self.assertEqual(sorted_names, expected)
  
imports: from ax.plot.helper import arm_name_to_sort_key, extend_range
  from ax.utils.common.testutils import TestCase
label_desc: Use image node_id 2 for calling the HelperTest obj's underlying member method code with example usage: obj.test_arm_name_to_sort_key() without return types