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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 saveVTK(self, filename):
 """ Save polygons in VTK file. """

        with open(filename, 'w') as f:
            f.write('# vtk DataFile Version 3.0\n')
            f.write('pycsg output\n')
            f.write('ASCII\n')
            f.write('DATASET POLYDATA\n')
        
            verts, cells, count = self.toVerticesAndPolygons()

            f.write('POINTS {0} float\n'.format(len(verts)))
            for v in verts:
                f.write('{0} {1} {2}\n'.format(v[0], v[1], v[2]))
            numCells = len(cells)
            f.write('POLYGONS {0} {1}\n'.format(numCells, count + numCells))
            for cell in cells:
                f.write('{0} '.format(len(cell)))
                for index in cell:
                    f.write('{0} '.format(index))
                f.write('\n')