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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def extract_geometry(dataset):
 """Extract the outer surface of a volume or structured grid dataset as PolyData. This will extract all 0D, 1D, and 2D cells producing the boundary faces of the dataset. """

        alg = vtk.vtkGeometryFilter()
        alg.SetInputDataObject(dataset)
        alg.Update()
        return _get_output(alg)