def lookup_executor (self, slave_id, executor_id):
        for exe in self._executors.values():
            if exe.slave_id == slave_id:
                return exe
Tests unimplemented TwitterOrder functions aiming for exceptions
dataset/ETHPy150Open ceteri/exelixi/src/resource.py/MesosScheduler.lookup_executor--crossover with--dataset/ETHPy150Open ckoepp/TwitterSearch/tests/test_tso.py/TwitterSearchOrderTest.test_TO_exceptions