code: def test_default_parameters_default():
      trainer = LightGBMTrainer(
          datasets={TRAIN_DATASET_KEY: ray.data.from_pandas(train_df)},
          label_column="target",
          params=params,
      )
      assert trainer._ray_params.cpus_per_actor == 2
  
imports: import math
  import lightgbm
  import pandas
  import pytest
  from sklearn.datasets import load_breast_cancer
  from sklearn.model_selection import train_test_split
  import ray
  from ray import tune
  from ray.train import ScalingConfig
  from ray.train.constants import TRAIN_DATASET_KEY
  from ray.train.lightgbm import LightGBMTrainer
label_desc: Use image node_id 9 for calling a global function with example usage: test_default_parameters_default() without return types