Err. compiling func. with SET TRANS...

Hello,

I'm having trouble getting functions with SET TRANSACTION ISOLATION ... to parse.

This is the error I'm getting (example function below the error):

=> select simple_fun();
NOTICE:  plpgsql: ERROR during compile of simple_fun near line 3
ERROR:  parse error at or near ";"

This is the simple_fun function that is causing the above error:

CREATE FUNCTION simple_fun() RETURNS INTEGER AS '
BEGIN SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; BEGIN; SELECT 1; END; RETURN 1;
END;
' LANGUAGE 'plpgsql';

This is as simple as it gets.
I think my syntax is correct (I checked Practical PostgreSQL book as well as a number of 7.2 PDF documents, etc.).

Am I missing a secret ingredient here?

Thank you,
Otis

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