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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_values(self, keys):
 """ Return a list of values associated to a particular list of keys. """

        if is_string(keys):
            return [s.__dict__[keys] for s in self.sections]
        else:
            values = []
            for k in keys:
                values.append([s.__dict__[k] for s in self.sections])
            return values