<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def crossvalidate_model(cls, clusterer, data, num_folds, rnd):
 """ 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 """

        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)