def _check_bad_exception_context(self, node):
        """Verify that the exception context is properly set.

        An exception context can be only `None` or an exception.
        """
        cause = utils.safe_infer(node.cause)
        if cause in (astroid.Uninferable, None):
            return

        if isinstance(cause, astroid.Const):
            if cause.value is not None:
                self.add_message("bad-exception-context", node=node)
        elif not isinstance(cause, astroid.ClassDef) and not utils.inherit_from_std_ex(
            cause
        ):
            self.add_message("bad-exception-context", node=node)
Verify that the exception context is properly set.

        An exception context can be only `None` or an exception.