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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 values(self):
 """ Returns a mapping of items to their new values. The mapping includes only items whose value or raw string value has changed in the context. """

        report = {}
        for k, k_changes in self._changes.items():
            if len(k_changes) == 1:
                report[k] = k_changes[0].new_value
            elif k_changes[0].old_value != k_changes[-1].new_value:
                report[k] = k_changes[-1].new_value
        return report