code: func (m *Manager) getAuthorizationRequest(authorizationcode string) (ar *authorizationRequest, err error) {
  	ar = &authorizationRequest{}
  
  	err = m.getAuthorizationRequestCollection().Find(bson.M{"authorizationcode": authorizationcode}).One(ar)
  	if err != nil && err == mgo.ErrNotFound {
  		ar = nil
  		err = nil
  		return
  	}
  	return
  }
docs: // Get an authorizationRequest by it's authorizationcode.