code: def create(kls, url, strict=True):
          
          app = kls.load(url)
          app.prepare(strict=strict)
  
          return app
docs: factory of App
  
          :param str url: url of path of Swagger API definition
          :param bool strict: when in strict mode, exception would be raised if not valid.
          :return: the created App object
          :rtype: App
          :raises ValueError: if url is wrong
          :raises NotImplementedError: the swagger version is not supported.