You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: group_repo.go
    path of file: ./repos/gim/internal/logic/domain/group/repo
    
    the code of the file until where you have to start completion: package repo

import (
	"gim/internal/logic/domain/group/entity"
)

type groupRepo struct{}

var GroupRepo = new(groupRepo)

// Get 获取群组信息
func (*groupRepo) Get(groupId int64) (*entity.Group, error) {
	group, err := GroupCache.Get(groupId)
	if err != nil {
		return nil, err
	}
	if group != nil {
		return group, nil
	}

	group, err = GroupDao.Get(groupId)
	if err != nil {
		return nil, err
	}
	members, err := GroupUserRepo.ListUser(groupId)
	if err != nil {
		return nil, err
	}
	group.Members
    
func (*groupRepo) Save(group *entity.Group) error {
	groupId := group.Id
	err := GroupDao.Save(group)
	if err != nil {
		return err
	}

	members := group.Members
	for i := range members {
		members[i].GroupId = group.Id
		if members[i].UpdateType == entity.UpdateTypeUpdate {
			err = GroupUserRepo.Save(&(members[i]))
			if err != nil {
				return err
			}
		}
		if members[i].UpdateType == entity.UpdateTypeDelete {
			err = GroupUserRepo.Delete(group.Id, members[i].UserId)
			if err != nil {
				return err
			}
		}
	}

	if groupId != 0 {
		err = GroupCache.Del(groupId)
		if err != nil {
			return err
		}
	}
	return nil
}