Oracle PL/SQL | Script to generate SQL for Primary contraint for all tables

declare
cursor get_cons is
select distinct dc.table_name table_name, decode ( substr(dc.constraint_name,1,3), 'SYS', ' ', 'CONSTRAINT ' dc.constraint_name ) contraint, wmsys.wm_concat(ucc.column_name) over ( partition by dc.constraint_name order by dc.constraint_name ) cols
from user_constraints dc,
user_cons_columns ucc
where dc.table_name like '%'
and dc.constraint_type = 'P'
and dc.table_name = ucc.table_name
and dc.constraint_name = ucc.constraint_name;
lv_sql varchar2(2000);
begin
for i in get_cons
loop
lv_sql := 'ALTER TABLE '
I.TABLE_NAME
' ADD ('
i.contraint
' PRIMARY KEY ( '
I.COLS
' )); ';
dbms_output.put_line( lv_sql );
end loop;
end;