How to use the streamz.batch.Batch function in streamz

All elements of the stream are assumed to be lists or tuples

        Examples
        --------
        >>> source = Stream()
        >>> batches = source.to_batch()
        >>> L = batches.pluck('value').map(inc).sum().stream.sink_to_list()
        >>> source.emit([{'name': 'Alice', 'value': 1},
        ...              {'name': 'Bob', 'value': 2},
        ...              {'name': 'Charlie', 'value': 3}])
        >>> source.emit([{'name': 'Alice', 'value': 4},
        ...              {'name': 'Bob', 'value': 5},
        ...              {'name': 'Charlie', 'value': 6}])
        """
        from .batch import Batch
        return Batch(stream=self, **kwargs)

def _pluck(seq, ind):
    return list(toolz.pluck(ind, seq))


def _map_map(seq, func, **kwargs):
    return list(map(func, seq, **kwargs))


def _accumulate_sum(accumulator, new):
    return accumulator + sum(new)


map_type = type(map(lambda x: x, []))

_stream_types['streaming'].append(((list, tuple, set), Batch))

def __init__(self, stream=None, example=None):
        if example is None:
            example = []
        super(Batch, self).__init__(stream=stream, example=example)