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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 wateryear(self):
 """The actual hydrological year according to the selected reference month. The reference mont reference |Date.refmonth| defaults to November: 1996 1997 Note that changing |Date.refmonth| affects all |Date| objects: 1997 1997 1996 1997 """

        if self.month < self._firstmonth_wateryear:
            return self.year
        return self.year + 1