code: def test_MergeDuplicateArm(self) -> None:
      arms = self.arms + [self.arms[0]]
      run = GeneratorRun(
          arms=arms,
          optimization_config=self.optimization_config,
          search_space=self.search_space,
          model_predictions=self.model_predictions,
      )
      self.assertEqual(str(run), GENERATOR_RUN_STR_PLUS_1)
  
file_path: Ax/ax/core/tests/test_generator_run.py
imports: from ax.core.arm import Arm
  from ax.core.generator_run import GeneratorRun
  from ax.exceptions.core import UnsupportedError
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_arms, get_model_predictions, get_model_predictions_per_arm, get_optimization_config, get_search_space
label_desc: Use image node_id 4 for calling the GeneratorRunTest obj's underlying member method code with example usage: obj.test_MergeDuplicateArm() without return types