code: def objective(**params):
      reg.set_params(**params)
  
      return -np.mean(
          cross_val_score(
              reg,
              X,
              y,
              cv=5,
              n_jobs=-1,
              scoring="neg_mean_absolute_error",
          )
      )
  
file_path: scikit-optimize/examples/hyperparameter-optimization.py
imports: import numpy
  from sklearn.datasets import load_boston
  from sklearn.ensemble import GradientBoostingRegressor
  from sklearn.model_selection import cross_val_score
  from skopt.space import Real, Integer
  from skopt.utils import use_named_args
  from skopt import gp_minimize
  from skopt.plots import plot_convergence
label_desc: Use image node_id 1 for calling a global function with example usage: objective() and returns: unknown