How to call a procedure in a package which has an OUT value?

How to call a procedure in a package which has an OUT value?

I have a sql procedure in a package which has a OUT parameter. Package
body is given bellow
create or replace
PACKAGE BODY TEST_PACKAGE AS -- body
Procedure TEST_PROCEDURE (
data_1 IN VARCHAR2
, data_2 IN VARCHAR2
, data_3 IN DATE
, out_data OUT VARCHAR2 )
IS
BEGIN
INSERT INTO TEST_TABLE(
COLUMN_1,
COLUMN_2,
COLUMN_3) VALUES(
data_1,
data_2,
data_3
);
out_data:='SUCCESS';
End TEST_PROCEDURE;
END TEST_PACKAGE;
I tried to invoke this procedure with the bellow SQL command.
DECLARE
sample_out_data VARCHAR2;
Begin
TEST_PACKAGE.TEST_PROCEDURE
('test_data_1','test_data_2','2012-02-23',sample_out_data);
END;
But it gives me errors. Can anyone please tell me how to call this procedure?