Hello everyone, I am writing this to ask about how can I finalize the sytem with translational invariance along two directions. Code that I am using is the following as I want to make a slab system for band structure. sym = kwant.TranslationalSymmetry([1, 0, 0], [0, 1, 0]) Error: ValueError: Currently, only builders without or with a 1D translational symmetry can be finalized. Is there any solution to this? I also happen to get one code from notes on internet by edx course where thwe following code has been used using wraparound function. I did not get much out of it. Also, I checked I don't have this function in my kwant module. how can I get this functions module? Please anyone can explian what this function is doing in the code: def make_scatter_sys(): from functions import wraparound syst = wraparound(bhz(Z=1, system_type='slab')) syst.attach_lead(make_lead()) syst.attach_lead(wraparound(bhz(), keep=0)) syst = syst.finalized() syst.leads[0] = TRIInfiniteSystem(syst.leads[0], trs) return syst ANANT VIJAY VARMA Research Scholar IISER-KOLKATA WEST BENGAL.