'Process this response as WSGI application.
:param environ: the WSGI environment.
:param start_response: the response callable provided by the WSGI
server.
:return: an application iterator'

def __call__(self, environ, start_response):

    (app_iter, status, headers) = self.get_wsgi_response(environ)
    start_response(status, headers)
    return app_iter
