can(what?)
transfer(user?, user_group?)
linkJoin(id)
linkAccess(access?, expires?, type?, mailto?)
setAccess(user?, user_group?, access?, expires?)
leaveAccess()
unsetAccess(user?, user_group?)
byType(type, verbose?)
getTypes(editable_only?)
listAccesses(MetaObject__, User_Group__, minimum?, recursive?)
listAccess(minimum?)
listChildrenAccess()