code: def test_map_partitions(self):
      """Test RDDBarrier.mapPartitions"""
      rdd = self.sc.parallelize(range(12), 4)
      self.assertFalse(rdd._is_barrier())
  
      rdd1 = rdd.barrier().mapPartitions(lambda it: it)
      self.assertTrue(rdd1._is_barrier())
  
imports: from pyspark.testing.utils import ReusedPySparkTestCase
label_desc: Use image node_id 1 for calling the RDDBarrierTests obj's underlying member method code with example usage: obj.test_map_partitions() without return types