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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 get_dates(self):
 """Get DataCite dates."""

        if 'dates' in self.xml:
            if isinstance(self.xml['dates']['date'], dict):
                return self.xml['dates']['date'].values()[0]
            return self.xml['dates']['date']
        return None