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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 tenure(self):
 """ Calculates board tenure in years """

        if self.end_date:
            return round((date.end_date - self.start_date).days / 365., 2)
        else:
            return round((date.today() - self.start_date).days / 365., 2)