def SetCachingHeaders(self):
    max_age = self.MAX_AGE
    self.response.headers['Expires'] = email.Utils.formatdate(
        time.time() + max_age, usegmt=True)
    cache_control = []
    if self.PUBLIC:
      cache_control.append('public')
    cache_control.append('max-age=%d' % max_age)
    self.response.headers['Cache-Control'] = ', '.join(cache_control)
    # adding caching headers for the client
    if self.CLIENT_CACHING:
        if self.current_last_modified:
            self.response.headers['Last-Modified'] = self.current_last_modified.strftime("%a, %d %b %Y %H:%M:%S GMT")
        if self.current_etag:
            self.response.headers['ETag'] = self.current_etag
API call:  test for the existence of the topic via a GET request
dataset/ETHPy150Open aehlke/manabi/apps/dojango/appengine/memcache_zipserve.py/MemcachedZipHandler.SetCachingHeaders--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/gcloud-python/gcloud/pubsub/topic.py/Topic.exists