predic object dm design dsgr todo wfr doesn restrict classifi tfm model facad classifi dm problem object classifi dm design materi model facad classifi equal unspec problem design materi design materi length problem collect element import model facad element import classifi element import problem todo check immedi sibl need check import element parent take account visibl iter iter element import iter iter object imp iter object pack model facad imp alia model facad alia imp alia alia length alia design materi collect sibl model facad own element pack sibl problem iter elem sibl iter elem object eo elem object model facad model element eo todo wfr doesn restrict classifi tfm model facad classifi classifi model facad equal equal alia problem problem 