Error thrown when creating BlockMatrix

dm1 = Matrices.dense(3, 2, [1, 2, 3, 4, 5, 6])
dm2 = Matrices.dense(3, 2, [7, 8, 9, 10, 11, 12])
sm = Matrices.sparse(3, 2, [0, 1, 3], [0, 1, 2], [7, 11, 12])
blocks1 = sc.parallelize([((0, 0), dm1)])
sm_ = Matrix(3,2,sm)
blocks2 = sc.parallelize([((0, 0), sm), ((1, 0), sm)])
blocks3 = sc.parallelize([((0, 0), sm), ((1, 0), dm2)])

mat2 = BlockMatrix(blocks2, 3, 2)
mat3 = BlockMatrix(blocks3, 3, 2)

Running above sample code in Pyspark from documentation raises following error: 

An error occurred while calling z:org.apache.spark.api.python.PythonRDD.runJob. : org.apache.spark.SparkException: Job aborted due to stage failure: Task 14 in stage 53.0 failed 4 times, most recent failure: Lost task 14.3 in stage 53.0 (TID 1081, , executor 15): org.apache.spark.api.python.PythonException: Traceback (most recent call last): File "/mnt/yarn/usercache/livy/appcache//pyspark.zip/pyspark/worker.py", line 230, in main process() File "/mnt/yarn/usercache/livy/appcache//pyspark.zip/pyspark/worker.py", line 225, in process serializer.dump_stream(func(split_index, iterator), outfile) File "/mnt/yarn/usercache/livy/appcache/application_1535051034290_0001/container_1535051034290_0001_01_000023/pyspark.zip/pyspark/serializers.py", line 372, in dump_stream vs = list(itertools.islice(iterator, batch)) File "/usr/lib/spark/python/lib/pyspark.zip/pyspark/rdd.py", line 1371, in takeUpToNumLeft File "/mnt/yarn/usercache/livy/appcache//pyspark.zip/pyspark/util.py", line 55, in wrapper return f(*args, **kwargs) File "/mnt/yarn/usercache/livy/appcache//pyspark.zip/pyspark/mllib/linalg/distributed.py", line 975, in _convert_to_matrix_block_tuple raise TypeError("Cannot convert type %s into a sub-matrix block tuple" % type(block)) TypeError: Cannot convert type <type 'tuple'> into a sub-matrix block tuple