the method
def _copperLayers(self):
coppers = [ (int(t),unquote(self.pcb.layers[t][0])) \
for t in self.pcb.layers if int(t)<=31]
coppers.sort(key=lambda x : x[0])
return coppers
makes the assumption that the first 32 layers are hardcoded to be copper, which doesn't seem to be the case anymore in current version of Kicad.
the method
fcad_pcb/kicad.py
Line 724 in 30e1f48
makes the assumption that the first 32 layers are hardcoded to be copper, which doesn't seem to be the case anymore in current version of Kicad.