model/graph: Topo_Diff: len__x_x utility methods
model/graph: Topo_Diff: len__x_x utility methods

cben/rhizi,ozFri/rhizi,cben/rhizi,cben/rhizi,Rhizi/rhizi,cben/rhizi,shlomif/rhizi,yuvadm/rhizi,shlomif/rhizi,tlevine/rhizi,ozFri/rhizi,Rhizi/rhizi,Rhizi/rhizi,tlevine/rhizi,Rhizi/rhizi,ozFri/rhizi,ozFri/rhizi,yuvadm/rhizi,tlevine/rhizi,yuvadm/rhizi,tlevine/rhizi,yuvadm/rhizi,shlomif/rhizi,shlomif/rhizi