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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 approximant(self, index):
 """ Return the name of the approximant ot use at the given index """

        if 'approximant' not in self.table.fieldnames:
            raise ValueError("approximant not found in input file and no "
                "approximant was specified on initialization")
        return self.table["approximant"][index]