set serveroutput on in oracle procedure

I've created a simple procedure. In this procedure i want to output some data. However where ever i put set serveroutput on

it says

Error(26,5): PLS-00103: Encountered the symbol "SERVEROUTPUT" when expecting one of the following: . ( ) , * @ % & = - + < / > at in is mod remainder not rem => <> or != or ~= >= <= <> and or like like2 like4 likec as between || multiset member submultiset

It doesn't matter where i put it, it keeps saying it.

create or replace PROCEDURE discount  

is --- signature 

BEGIN --- executable part

update dvd set me_our_price = me_our_price*0.90 WHERE me_release_year = 2011;
update dvd set me_our_price = me_our_price*0.80 WHERE me_release_year = 2010;

update bluray set me_our_price = me_our_price*0.95 WHERE me_release_year = 2011;
update bluray set me_our_price = me_our_price*0.90 WHERE me_release_year = 2010;


DBMS_OUTPUT.PUT_LINE(' Blurays '); 
for i in ( 
SELECT e.mo_title, e.mo_bluray.me_list_price as me_list_price, e.mo_bluray.me_our_price    as  me_our_price FROM movie e  where e.mo_bluray is not null
 ) 
loop 

DBMS_OUTPUT.PUT_LINE(i.mo_title|| '  ' || i.me_list_price|| '  ' || i.me_list_price); 

end loop; 

DBMS_OUTPUT.PUT_LINE(' DVDs '); 
for i in ( 
set serveroutput on
SELECT e.mo_title, e.mo_dvd.me_list_price as me_list_price, e.mo_dvd.me_our_price as      me_our_price FROM movie e  where e.mo_dvd is not null
 ) 
loop 
DBMS_OUTPUT.PUT_LINE(i.mo_title|| '  ' || i.me_list_price|| '  ' || i.me_list_price); 
end loop; 


END discount;