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 reset_should_print_backtrace_to_terminal(cls, should_print_backtrace):
        """Set whether a backtrace gets printed to the terminal error stream on a fatal error.

        Class state:
        - Overwrites `cls._should_print_backtrace_to_terminal`.
        """
        cls._should_print_backtrace_to_terminal = should_print_backtrace