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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def persist(self, storageLevel):
 """ Persists the underlying RDD with the specified storage level. """

        if not isinstance(storageLevel, StorageLevel):
            raise TypeError("`storageLevel` should be a StorageLevel, got %s" % type(storageLevel))
        javaStorageLevel = self._java_matrix_wrapper._sc._getJavaStorageLevel(storageLevel)
        self._java_matrix_wrapper.call("persist", javaStorageLevel)
        return self