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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 _pwl1_to_poly(self, generators):
 """ Converts single-block piecewise-linear costs into linear polynomial. """

        for g in generators:
            if (g.pcost_model == PW_LINEAR) and (len(g.p_cost) == 2):
                g.pwl_to_poly()

        return generators