def _MakeCacheInvariant(self, urn, token, age):
    return "%s:%s:%s" % (utils.SmartStr(urn), utils.SmartStr(token),
                         self.ParseAgeSpecification(age))
Returns an invariant key for an AFF4 object.
dataset/ETHPy150Open google/grr/grr/lib/aff4.py/Factory._MakeCacheInvariant