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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 rebind_string(self, keysym, newstring):
 """Change the translation of KEYSYM to NEWSTRING. If NEWSTRING is None, remove old translation if any. """

        if newstring is None:
            try:
                del self.keysym_translations[keysym]
            except KeyError:
                pass
        else:
            self.keysym_translations[keysym] = newstring