完成以下PL/SQL块，功能是：使用游标，显示所有单价低于250元的玩具的单价。
DECLARE
my_toy_price toys.toyprice%TYPE; CURSOR toy_cur IS
SELECT toyprice FROM toys WHERE toyprice<250; BEGIN
______________ LOOP
________________________________________ EXIT WHEN toy_cur%NOTFOUND;
DBMS_OUTPUT.PUT_LINE (toy_cur%ROWCOUNT || '. 玩具单价:' || my_toy_price); END LOOP;
CLOSE toy_cur; END;