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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 covariance(self,pt0,pt1):
 """get the covariance between two points implied by the GeoStruct. This is used during the ordinary kriging process to get the RHS Parameters pt0 : (iterable length 2 of floats) pt1 : (iterable length 2 of floats) Returns ------- covariance : float the covariance between pt0 and pt1 implied by the GeoStruct """

        #raise Exception()
        cov = self.nugget
        for vario in self.variograms:
            cov += vario.covariance(pt0,pt1)
        return cov