How to use the snakeviz.handler.Handler function in snakeviz

# test whether this can be opened with pstats
        try:
            pstats.Stats(sfilename)

        except:
            os.remove(sfilename)
            error = 'There was an error parsing {0} with pstats.'
            error = error.format(filename)
            self.render('upload.html', error=error)

        else:
            self.redirect('viz/' + filename)


class JSONHandler(handler.Handler):
    """
    Handler for requesting the JSON representation of a profile.
    """

    _timer = None
    _pool = None
    _timeout = None
    _result = None

    @asynchronous
    def get(self, prof_name):
        if self.request.path.startswith('/json/file/'):
            if self.settings['single_user_mode']:
                if prof_name[0] != '/' and platform.system() != 'Windows':
                    prof_name = '/' + prof_name
                filename = os.path.abspath(prof_name)