code: def test__check_reg_targets():
      # All of length 3
      EXAMPLES = [
          ("continuous", [1, 2, 3], 1),
          ("continuous", [[1], [2], [3]], 1),
          ("continuous-multioutput", [[1, 1], [2, 2], [3, 1]], 2),
          ("continuous-multioutput", [[5, 1], [4, 2], [3, 1]], 2),
          (
              "continuous-multioutput",
              [[1, 3, 4], [2, 2, 2], [3, 1, 1]],
              3,
          ),
      ]
  
      for (type1, y1, n_out1), (type2, y2, n_out2) in product(
          EXAMPLES, repeat=2
      ):
          if type1 == type2 and n_out1 == n_out2:
              (
                  y_type,
                  y_check1,
                  y_check2,
                  multioutput,
              ) = _check_reg_targets(y1, y2, None)
              assert type1 == y_type
              if type1 == "continuous":
                  assert_array_equal(y_check1, np.reshape(y1, (-1, 1)))
                  assert_array_equal(y_check2, np.reshape(y2, (-1, 1)))
              else:
                  assert_array_equal(y_check1, y1)
                  assert_array_equal(y_check2, y2)
          else:
              with pytest.raises(ValueError):
                  _check_reg_targets(y1, y2, None)
  
imports: from itertools import product
  import numpy
  import pytest
  from numpy.testing import assert_allclose
  from scipy import optimize
  from scipy.special import factorial, xlogy
  from sklearn.dummy import DummyRegressor
  from sklearn.exceptions import UndefinedMetricWarning
  from sklearn.metrics import d2_absolute_error_score, d2_pinball_score, d2_tweedie_score, explained_variance_score, make_scorer, max_error, mean_absolute_error, mean_absolute_percentage_error, mean_pinball_loss, mean_squared_error, mean_squared_log_error, mean_tweedie_deviance, median_absolute_error, r2_score, root_mean_squared_error, root_mean_squared_log_error
  from sklearn.metrics._regression import _check_reg_targets
  from sklearn.model_selection import GridSearchCV
  from sklearn.utils._testing import assert_almost_equal, assert_array_almost_equal, assert_array_equal
label_desc: Use image node_id 5 for calling a global function with example usage: test__check_reg_targets() without return types