code: def test_AddArm(self) -> None:
      self.assertEqual(len(self.batch.arms), len(self.arms))
      self.assertEqual(len(self.batch.generator_run_structs), 1)
      self.assertEqual(sum(self.batch.weights), sum(self.weights))
  
      arm_parameters = get_arm().parameters
      arm_parameters["w"] = 5.0
      self.batch.add_arm(Arm(arm_parameters), 3)
  
      self.assertEqual(
          self.batch.arms_by_name["0_2"], self.batch.arms[2]
      )
      self.assertEqual(len(self.batch.arms), len(self.arms) + 1)
      self.assertEqual(len(self.batch.generator_run_structs), 2)
      self.assertEqual(sum(self.batch.weights), sum(self.weights) + 3)
  
imports: import math
  from time import sleep
  from unittest import mock
  from unittest.mock import patch, PropertyMock
  import numpy
  from ax.core.arm import Arm
  from ax.core.base_trial import TrialStatus
  from ax.core.batch_trial import BatchTrial, GeneratorRunStruct
  from ax.core.experiment import Experiment
  from ax.core.generator_run import GeneratorRun, GeneratorRunType
  from ax.core.parameter import FixedParameter, ParameterType
  from ax.core.search_space import SearchSpace
  from ax.runners.synthetic import SyntheticRunner
  from ax.utils.common.testutils import TestCase
  from ax.utils.common.typeutils import checked_cast
  from ax.utils.testing.core_stubs import get_abandoned_arm, get_arm, get_arm_weights1, get_arms, get_experiment, get_generator_run, get_generator_run2, get_weights
label_desc: Use image node_id 6 for calling the BatchTrialTest obj's underlying member method code with example usage: obj.test_AddArm() without return types