When user add/update/delete access for AclEntity (project, model, cube, job), which will check user exist. But if there are two user not exist, which will cause issue. Admin want to delete the notExistsUser1, it will throws notExistsUser2 not exist. The other operation has same issues for this check. Could we add another method for checkExistUser and just add the method for add or update? It should be fix this issue.