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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 getEstTraitCovar(self,term_i=None):
 """ Returns explicitly the estimated trait covariance matrix Args: term_i: index of the term we are interested in """

        assert self.P>1, 'Trait covars not defined for single trait analysis'
        
        if term_i==None:
            RV=SP.zeros((self.P,self.P))
            for term_i in range(self.n_terms): RV+=self.vd.getTerm(term_i).getTraitCovar().K()
        else:
            assert term_i<self.n_terms, 'Term index non valid'
            RV = self.vd.getTerm(term_i).getTraitCovar().K()
        return RV