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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 prev(self):
 """ Generate query parameters for the prev page """


        if self.total:
            if self.offset - self.limit - self.limit < 0:
                return self.first
            else:
                offset = self.offset - self.limit
                return {'page[offset]': offset, 'page[limit]': self.limit}
        else:
            return None