def wsgi_a(env, start_response): start_response("200", [("Content-Length", "1")]) return [b"1"] def wsgi_b(env, start_response): start_response("200", [("Content-Length", "1")]) return [b"2"] def wsgi_a_factory(): return wsgi_a def wsgi_b_factory(): return wsgi_b wsgi_invalid_callable = None def wsgi_factory_returning_invalid_callable(): return wsgi_invalid_callable