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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 update(self):
 """Replace baseline representations previously registered for update."""

        for linenum in reversed(sorted(self.updates)):
            self.replace_baseline_repr(linenum, self.updates[linenum])

        if not self.TEST_MODE:
            path = '{}.update{}'.format(*os.path.splitext(self.path))
            with io.open(path, 'w', encoding='utf-8') as fh:
                fh.write('\n'.join(self.lines))
            print('UPDATE: {}'.format(self.showpath(path)))