[Kwant] how to define make_system?

Dear all, I am new to Kwant and python, and I am trying out Kwant by learning the examples. I have tried a simple squre scattering region like this: def make_system(a=1, t=-2.8, W=9, L=10): lat = kwant.lattice.honeycomb() def squre(pos): x, y = pos return 0<=x<=L and 0<=y<=W sys = kwant.Builder() i want to try more complicated shapes, for example 0<=x<=L, 0<=y<=W and 2L<=x<=3L,0<=y<=2W. how shoud i change my programme? i note that in the previous version Knit we can glue two regions easily,can we do this in Kwant similarly？ Thanks! Regards, Qingtian Zhang