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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 pluck(self, value, key=None):
 """ Get a list with the values of a given key. :rtype: Collection """

        if key:
            return dict(map(lambda x: (data_get(x, key), data_get(x, value)), self.items))
        else:
            results = list(map(lambda x: data_get(x, value), self.items))

        return self.__class__(results)