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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 obfn_fvar(self):
 """Variable to be evaluated in computing regularisation term, depending on 'fEvalX' option value. """


        if self.opt['fEvalX']:
            return self.X
        else:
            return self.cnst_c() - self.cnst_B(self.Y)