code: def naive_multivariate_forecaster(
      ts, prediction_length, num_samples=100
  ):
      return naive_forecaster(
          ts, prediction_length, num_samples, target_dim=1
      )
  
file_path: gluonts/test/evaluation/test_evaluator.py
imports: import numpy
  import pandas
  import pytest
  from gluonts.evaluation import Evaluator, MultivariateEvaluator, aggregate_valid
  from gluonts.model.forecast import QuantileForecast, SampleForecast
label_desc: Use image node_id 4 for calling a global function with example usage: naive_multivariate_forecaster(ts, prediction_length, num_samples) and returns: naive_forecaster