def test_formatDelayedCallsAndSelectables(self):
        """
        Both delayed calls and selectables can appear in the same error.
        """
        error = DirtyReactorAggregateError(["bleck", "Boozo"],
                                           ["Sel1", "Sel2"])
        self.assertEqual(str(error),
                          """\
Reactor was unclean.
DelayedCalls: (set twisted.internet.base.DelayedCall.debug = True to debug)
bleck
Boozo
Selectables:
Sel1
Sel2""")

        Both delayed calls and selectables can appear in the same error.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_util.py