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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 restore_attr(self, attr_name):
 """Restore an attribute back onto the target object. :param str attr_name: the name of the attribute to restore """

        original_attr = self._original_attr(attr_name)
        if self._original_attr(attr_name):
            setattr(self.obj.__class__, attr_name, original_attr)