code: func (m *Manager) UpdateClient(clientID, oldLabel, newLabel string, callbackURL string, clientcredentialsGrantType bool) (err error) {
  
  	_, err = m.getClientsCollection().UpdateAll(bson.M{"clientid": clientID, "label": oldLabel}, bson.M{"$set": bson.M{"label": newLabel, "callbackurl": callbackURL, "clientcredentialsgranttype": clientcredentialsGrantType}})
  
  	if err != nil && mgo.IsDup(err) {
  		err = db.ErrDuplicate
  	}
  	return
  }
docs: //UpdateClient updates the label, callbackurl and clientCredentialsGrantType properties of a client