def test_systemDeprecatedWriteFailure(self):
        if Failure is None:
            raise SkipTest("Twisted unavailable")

        logger = MemoryLogger()
        with catch_warnings(record=True) as warnings:
            simplefilter("always")
            try:
                raise Exception()
            except:
                writeFailure(Failure(), logger, "system")
            self.assertEqual(warnings[-1].category, DeprecationWarning)
returns: float with percentage of relative humidity
dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_traceback.py/TracebackLoggingTests.test_systemDeprecatedWriteFailure--crossover with--dataset/ETHPy150Open EricssonResearch/calvin-base/calvin/runtime/south/plugins/io/sensors/environmental/base_environmental.py/EnvironmentalBase.get_humidity