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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 selected(self, new):
 """Set selected from list or instance of object or name. Over-writes existing selection """

        def preprocess(item):
            if isinstance(item, str):
                return self.options[item]
            return item
        items = coerce_to_list(new, preprocess)
        self.widget.value = items