Fix exception handler type hints

import sys

import traceback

from io import StringIO

from typing import cast

from typing import (

    cast,

    Optional,

)

import markupsafe

from paste import (

            return app_iter

        return CatchingIter(app_iter, environ, sr_checker, self)

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

    def exception_handler(self, exc_info, environ) -> Optional[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:

) -> Optional[str]:

    """

    For exception handling outside of a web context