def index(self):
        """Produce HTTP response body of error display app index URI."""
        # display some links that will result in errors
        tracebacks = cherrypy.request.show_tracebacks
        if tracebacks:
            trace = 'off'
        else:
            trace = 'on'

        return (
            """
        <html><body>
            <p>Toggle tracebacks <a href="toggleTracebacks">%s</a></p>
            <p><a href="/doesNotExist">Click me; I'm a broken link!</a></p>
            <p>
              <a href="/error?code=403">
                Use a custom error page from a file.
              </a>
            </p>
            <p>These errors are explicitly raised by the application:</p>
            <ul>
                <li><a href="/error?code=400">400</a></li>
                <li><a href="/error?code=401">401</a></li>
                <li><a href="/error?code=402">402</a></li>
                <li><a href="/error?code=500">500</a></li>
            </ul>
            <p><a href="/messageArg">You can also set the response body
            when you raise an error.</a></p>
        </body></html>
        """
            % trace
        )
Produce HTTP response body of error display app index URI.
cherrypy/tutorial/tut10_http_errors.py