code: func (c *MemoryGroupService) GroupRemoveMember(ctx context.Context, groupName, uid string) error {
  	memoryGroupsMu.Lock()
  	defer memoryGroupsMu.Unlock()
  
  	mg, ok := memoryGroups[groupName]
  	if !ok {
  		return constants.ErrGroupNotFound
  	}
  	index, contains := elementIndex(mg.Uids, uid)
  	if contains {
  		mg.Uids[index] = mg.Uids[len(mg.Uids)-1]
  		mg.Uids = mg.Uids[:len(mg.Uids)-1]
  		memoryGroups[groupName] = mg
  		return nil
  	}
  
  	return constants.ErrMemberNotFound
  }
docs: // GroupRemoveMember removes specific UID from group