how to check leap-year

[jmodic]

create or replace function is_leap_year
 (p_year in number)
return varchar2
is
  l_dummy date;
begin
  select to_date('29.02.' || p_year, 'dd.mm.yyyy')
    into l_dummy
    from dual;
  return 'TRUE';
exception
  when others then return 'FALSE';
end;
/