bug while reading dxf files

[coder432]

`from Goulib.drawing import *

d = Drawing("house design.dxf")`
Results in error
/.local/lib/python3.6/site-packages/Goulib/drawing.py in from_dxf(self, dxf, layers, only, ignore, trans, flatten)
682 t2 = trans*Trans(e.scale[:2], e.insert[:2], e.rotation)
683 if flatten:
--> 684 self.from_dxf(self.block[e.name].dxf, layers=None, ignore=ignore, only=None, trans=t2, flatten=flatten)
685 else:
686 self.append(Instance.from_dxf(e, self.block, t2))

AttributeError: 'Group' object has no attribute 'block'