Problem with collections, casting and ORA 904

TYPE t_stfr_rec AS OBJECT
 (
 stfa_id NUMBER
,datestamp DATE
,withdrawal_qty NUMBER
,injection_qty NUMBER
,period_start DATE
,period_end DATE

  );

TYPE t_stfr_table AS TABLE OF t_stfr_rec;

and a function defined as:

FUNCTION get_stfr
RETURN t_stfr_table;

I thought that I would be able to access this type using

SELECT * FROM table(get_stfr AS t_stfr_table))

[Quoted] but I get an ORA 904 referring to get_stfr.

What am I doing wrong?

Andy

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