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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_note_names(self):
 """Return a list of unique note names in the Bar."""

        res = []
        for cont in self.bar:
            for x in cont[2].get_note_names():
                if x not in res:
                    res.append(x)
        return res