def serve_image(self, environ, start_response):
    """Dynamically serve an image from blobstore."""
    blobkey, options = self._parse_path(environ['PATH_INFO'])
    # Make sure that the blob URL has been registered by
    # calling get_serving_url
    key = datastore.Key.from_path(_BLOB_SERVING_URL_KIND, blobkey, namespace='')
    try:
      datastore.Get(key)
    except datastore_errors.EntityNotFoundError:
      logging.error('The blobkey %s has not registered for image '
                    'serving. Please ensure get_serving_url is '
                    'called before attempting to serve blobs.', blobkey)
      start_response(httplib.responses[404] % '404 %s', [])
      return []
    image, mime_type = self._transform_image(blobkey, options)
    start_response('200 OK', [
        ('Content-Type', mime_type),
        ('Cache-Control', 'public, max-age=600, no-transform')])
    return [image]
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/tools/devappserver2/blob_image.py/Application.serve_image/swapped operands of `%`