def _handle_request(self, request):
        future = self.executor.submit(request.run)
        return future
For the given sets of length k, returns combined candidate sets of length k+1.
dataset/ETHPy150Open smore-inc/tinys3/tinys3/pool.py/Pool._handle_request--crossover with--dataset/ETHPy150Open clips/pattern/pattern/vector/__init__.py/Apriori.Ck