code: def test_validate_params_missing_params():
      """Check that no error is raised when there are parameters without
      constraints
      """
  
      @validate_params({"a": [int]}, prefer_skip_nested_validation=True)
      def func(a, b):
          pass
  
      func(1, 2)
  
imports: from numbers import Integral, Real
  import numpy
  import pytest
  from scipy.sparse import csr_matrix
  from sklearn.base import BaseEstimator
  from sklearn.model_selection import LeaveOneOut
  from sklearn.utils import deprecated
  from imblearn._config import config_context, get_config
  from imblearn.base import _ParamsValidationMixin
  from imblearn.utils._param_validation import HasMethods, Hidden, Interval, InvalidParameterError, MissingValues, Options, RealNotInt, StrOptions, _ArrayLikes, _Booleans, _Callables, _CVObjects, _InstancesOf, _IterablesNotString, _NoneConstraint, _PandasNAConstraint, _RandomStates, _SparseMatrices, _VerboseHelper, generate_invalid_param_val, generate_valid_param, make_constraint, validate_params
  from imblearn.utils.fixes import _fit_context
label_desc: Use image node_id 18 for calling a global function with example usage: test_validate_params_missing_params() without return types