Return byte strings for error html

                start_response("500 Internal Server Error", [("content-type", "text/html")], exc_info)

                # @@: it would be nice to deal with bad content types here

                response = self.exception_handler(exc_info, environ)

                return [response]

                return [response.encode(errors="ignore")]

            finally:

                # clean up locals...

                exc_info = None

            return app_iter

        return CatchingIter(app_iter, environ, sr_checker, self)

    def exception_handler(self, exc_info, environ):

    def exception_handler(self, exc_info, environ) -> str:

        simple_html_error = False

        if self.xmlhttp_key:

            get_vars = wsgilib.parse_querystring(environ)

    error_message=None,

    simple_html_error=False,

    environ=None,

):

) -> str:

    """

    For exception handling outside of a web context