numpy_interface.dataset_adapter vtkPolydata issue: getting vtkLine cells

Hello,

it appears that getting cells in vtkPolydata with cells = dsa.WrapDataObject(self).Polygons is limited to vtkPolygon cells (including e.g. vtkTriangle cells). However vtkPolydata can also be used to represent polylines composed of vtkLine cells, but in this case the Polygons method returns a void array.

This is a problem in some application!

Thanks very much!