code: def test_cv_objects():
      """Check that the _CVObjects constraint accepts all current ways
      to pass cv objects."""
      constraint = _CVObjects()
      assert constraint.is_satisfied_by(5)
      assert constraint.is_satisfied_by(LeaveOneOut())
      assert constraint.is_satisfied_by(
          [([1, 2], [3, 4]), ([3, 4], [1, 2])]
      )
      assert constraint.is_satisfied_by(None)
      assert not constraint.is_satisfied_by("not a CV object")
  
imports: from numbers import Integral, Real
  import numpy
  import pytest
  from scipy.sparse import csr_matrix
  from sklearn._config import config_context, get_config
  from sklearn.base import BaseEstimator, _fit_context
  from sklearn.model_selection import LeaveOneOut
  from sklearn.utils import deprecated
  from sklearn.utils._param_validation import HasMethods, Hidden, Interval, InvalidParameterError, MissingValues, Options, RealNotInt, StrOptions, _ArrayLikes, _Booleans, _Callables, _CVObjects, _InstancesOf, _IterablesNotString, _NanConstraint, _NoneConstraint, _PandasNAConstraint, _RandomStates, _SparseMatrices, _VerboseHelper, generate_invalid_param_val, generate_valid_param, make_constraint, validate_params
label_desc: Use image node_id 31 for calling a global function with example usage: test_cv_objects() without return types