small issue in the documentation

[NickStrange]

In the getting started with TDD and utplsql

under Define tested function

create or replace function betwnstr( a_string varchar2, a_start_pos integer, a_end_pos integer ) return varchar2
is
begin
return substr( a_string, l_start_pos, a_end_pos - a_start_pos );
end;
/
l_start_pos should be a_start_pos