def test_iadd(self, evt):
        rval = event.ReturnValue(append_events=[evt])
        rval2 = event.ReturnValue(eat=True, append_events=[evt])
        rset = event.ResultSet()

        rset += rval
        rset += rval2
        rset += None
        assert rset.eat
        assert rset.append_events == [evt, evt]
def ignoring_sigint(cls):
        """A contextmanager which disables handling sigint in the current signal handler. This
        allows threads that are not the main thread to ignore sigint.

        NB: Only use this if you can't use ExceptionSink.trapped_signals().

        Class state:
        - Toggles `self._ignore_sigint` in `cls._signal_handler`.
        """
        with cls._signal_handler._ignoring_sigint():
            yield