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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 pad_position_w(self, i):
 """ Determines the position of the ith pad in the width direction. Assumes equally spaced pads. :param i: ith number of pad in width direction (0-indexed) :return: """

        if i >= self.n_pads_w:
            raise ModelError("pad index out-of-bounds")
        return (self.width - self.pad_width) / (self.n_pads_w - 1) * i + self.pad_width / 2