code: def test_traceback_tuner(ray_start_2_cpus):
      """Ensure that the Tuner's stack trace is not too long."""
  
      def failing(config):
          raise RuntimeError("Error")
  
      tuner = Tuner(failing)
      results = tuner.fit()
      assert len(str(results[0].error).split("\n")) <= 12
  
file_path: ray/python/ray/air/tests/test_tracebacks.py
imports: import pytest
  import ray
  from ray.train import ScalingConfig
  from ray.air._internal.util import StartTraceback, skip_exceptions
  from ray.train.data_parallel_trainer import DataParallelTrainer
  from ray.tune import Tuner
label_desc: Use image node_id 4 for calling a global function with example usage: test_traceback_tuner(ray_start_2_cpus) without return types