Given a free-standing function 'callable', return a new
        callable that will call 'callable' and report all exceptins,
        using 'call_and_report_errors'.

def make_wrapper(self, callable_):
        """Given a free-standing function 'callable', return a new
        callable that will call 'callable' and report all exceptins,
        using 'call_and_report_errors'."""
        assert callable(callable_)
        def wrapper(*args, **kw):
            return self.call_and_report_errors(callable_, *args, **kw)
        return wrapper