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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 save(self, output=None):
 """ Save the database to a file. If ``output`` is not given, the ``dbfile`` given in the constructor is used. """

        if output is None:
            if self.dbfile is None:
                return
            output = self.dbfile

        with open(output, 'w') as f:
            f.write(self._dump())