func init() { boltType = graph.RegisterIterator("bolt") }
func init() { mongoType = graph.RegisterIterator("mongo") }
func init() { gaedatastoreType = graph.RegisterIterator("gaedatastore") }
func init() { memType = graph.RegisterIterator("b+tree") }
func init() { levelDBType = graph.RegisterIterator("leveldb") }
func init() { sqlType = graph.RegisterIterator("sql") }
func init() { lmdbType = graph.RegisterIterator("lmdb") }
func init() { memType = graph.RegisterIterator("llrb") }
func init() { linksToType = graph.RegisterIterator("mongo-linksto") }