code: def get_test_class_registry():
      """Return test class registry.
  
      Wrapped in a function to avoid circular imports.
  
      Returns
      -------
      testclass_dict : dict
          test class registry
          keys are scitypes, values are test classes TestAll[Scitype]
      """
      from sktime.alignment.tests.test_all_aligners import (
          TestAllAligners,
      )
      from sktime.classification.early_classification.tests.test_all_early_classifiers import (  # noqa E501
          TestAllEarlyClassifiers,
      )
      from sktime.classification.tests.test_all_classifiers import (
          TestAllClassifiers,
      )
      from sktime.dists_kernels.tests.test_all_dist_kernels import (
          TestAllPairwiseTransformers,
          TestAllPanelTransformers,
      )
      from sktime.forecasting.tests.test_all_forecasters import (
          TestAllForecasters,
      )
      from sktime.param_est.tests.test_all_param_est import (
          TestAllParamFitters,
      )
      from sktime.proba.tests.test_all_distrs import (
          TestAllDistributions,
      )
      from sktime.regression.tests.test_all_regressors import (
          TestAllRegressors,
      )
      from sktime.tests.test_all_estimators import (
          TestAllEstimators,
          TestAllObjects,
      )
      from sktime.transformations.tests.test_all_transformers import (
          TestAllTransformers,
      )
  
      testclass_dict = dict()
      # every object in sktime inherits from BaseObject
      # "object" tests are run for all objects
      testclass_dict["object"] = TestAllObjects
      # fittable objects inherit from BaseEstimator
      # "estimator" tests are run for all estimators
      # estimators are also objects
      testclass_dict["estimator"] = TestAllEstimators
      # more specific base classes
      # these inherit either from BaseEstimator or BaseObject,
      # so also imply estimator and object tests, or only object tests
      testclass_dict["aligner"] = TestAllAligners
      testclass_dict["classifier"] = TestAllClassifiers
      testclass_dict["distribution"] = TestAllDistributions
      testclass_dict["early_classifier"] = TestAllEarlyClassifiers
      testclass_dict["forecaster"] = TestAllForecasters
      testclass_dict["param_est"] = TestAllParamFitters
      testclass_dict["regressor"] = TestAllRegressors
      testclass_dict["transformer"] = TestAllTransformers
      testclass_dict[
          "transformer-pairwise"
      ] = TestAllPairwiseTransformers
      testclass_dict[
          "transformer-pairwise-panel"
      ] = TestAllPanelTransformers
  
      return testclass_dict
  
label_desc: Use image node_id 1 for calling a global function with example usage: get_test_class_registry() and returns: testclass_dict