def __init__(self, node):
        super(_StreamNodeThread, self).__init__()
        self.node = node
        self.exception = None
        self.traceback = None
        self.logger = get_logger()
given a generator of pairs (x,y), generate one x for each value of y
dataset/ETHPy150Open Stiivi/brewery/brewery/streams.py/_StreamNodeThread.__init__--crossover with--dataset/ETHPy150Open Microsoft/ivy/src/ivy/ivy_utils.py/unique2