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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 cellCenters(self):
 """Get the list of cell centers of the mesh surface. .. hint:: |delaunay2d| |delaunay2d.py|_ """

        vcen = vtk.vtkCellCenters()
        vcen.SetInputData(self.polydata(True))
        vcen.Update()
        return vtk_to_numpy(vcen.GetOutput().GetPoints().GetData())