code: def objective(z, x):
      """Objective for SALSA with energy dataset."""
      num_tr_data_to_use = _get_tr_dataset_size_from_z0(z[0])
      return salsa_compute_negative_validation_error(
          x, num_tr_data_to_use
      )
  
imports: import numpy
  import pickle
  from salsa_estimator import salsa_train_and_validate
label_desc: Use image node_id 3 for calling a global function with example usage: objective(z, x) and returns: salsa_compute_negative_validation_error