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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 value(cls, obj, keystr):
 """ gets the value corresponding to keys from obj. if keys is a template string, it extrapolates the keys in it """

        if "#{" in keystr:
            # it's a template with keys vars
            keys = cls.from_template(keystr)
            for k in keys:
                v = cls.fetch(obj, cls.extract(k))
                keystr = keystr.replace(k, str(v))

            value = keystr
        else:
            # plain keys str
            value = cls.fetch(obj, keystr)

        return value