create temp function not supported

Are creating temp functions in the SQL statement not supported?
I used `Analyzer.extractTableNamesFromStatement` for this query:
```sql
CREATE TEMPORARY FUNCTION plusone(value INT64)
RETURNS INT64
LANGUAGE js AS """
return parseInt(value) + 1;
""";

SELECT plusone(1) AS two;
```
gives an error
`com.google.zetasql.io.grpc.StatusRuntimeException: INVALID_ARGUMENT: Syntax error: Unexpected keyword SELECT`