code: def crossvalidate_model(cls, clusterer, data, num_folds, rnd):
          
          return javabridge.static_call(
              "Lweka/clusterers/ClusterEvaluation;", "crossValidateModel",
              "(Lweka/clusterers/DensityBasedClusterer;Lweka/core/Instances;ILjava/util/Random;)D",
              clusterer.jobject, data.jobject, num_folds, rnd.jobject)
docs: Cross-validates the clusterer and returns the loglikelihood.
  
          :param clusterer: the clusterer instance to evaluate
          :type clusterer: Clusterer
          :param data: the data to evaluate on
          :type data: Instances
          :param num_folds: the number of folds
          :type num_folds: int
          :param rnd: the random number generator to use
          :type rnd: Random
          :return: the cross-validated loglikelihood
          :rtype: float