code: func (c *SessionContext) ExtendWebSession() (services.WebSession, error) {
  	sess, err := c.clt.ExtendWebSession(c.user, c.sess.GetName())
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return sess, nil
  }
docs: // ExtendWebSession creates a new web session for this user
  // based on the previous session