create function

I have installed plpgsql procedural language ok,
I could not get any functions to work. 
I tried the most simple function as documented:
CREATE FUNCTION sptest3 (int4) RETURNS int4 AS
	'BEGIN
		RETURN $1+1;
	END;' LANGUAGE 'plpgsql';


When i call the function from sql
SELECT sptest3(4) AS x;
I get the error:

"NOTICE:  plpgsql: ERROR during compile of sptest3 near line 1
"RROR:  parse error at or near "

can anybody help?