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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 sill(self):
 """ get the sill of the GeoStruct Return ------ sill : float the sill of the (nested) GeoStruct, including nugget and contribution from each variogram """

        sill = self.nugget
        for v in self.variograms:
            sill += v.contribution
        return sill