Extract all the internal/external edges of the dataset as PolyData.
        This produces a full wireframe representation of the input dataset.

def wireframe(dataset):
        """Extract all the internal/external edges of the dataset as PolyData.
        This produces a full wireframe representation of the input dataset.
        """
        alg = vtk.vtkExtractEdges()
        alg.SetInputDataObject(dataset)
        alg.Update()
        return _get_output(alg)