code: def _get_memcache_timeout(self, key, options=None):
      
      timeout = ContextOptions.memcache_timeout(options)
      if timeout is None:
        timeout = self._memcache_timeout_policy(key)
      if timeout is None:
        timeout = ContextOptions.memcache_timeout(self._conn.config)
      if timeout is None:
        timeout = 0
      return timeout
docs: Return the memcache timeout (expiration) for this key.