How to change the Wild Pokemon Battle BGM in a Map for legendary?

I want to know how to change the wild battle BGM for legendary in a map.
How to change a Encounter Battle BGM to another one,I want to define it for legendary Pokemon.:|

In PokemonField script section, about at line 1000, in def pbWildBattle, when the script say "$PokemonGlobal.nextBattleBGM=nil", you can make a little variation by replacing it with (RAYQUAZA is a little example):

if(species==PBSpecies,:RAYQUAZA) then
$PokemonGlobal.nextBattleBGM=("Audio/BGM/YourTheme")
else
$PokemonGlobal.nextBattleBGM=nil
end

It gave an error:

Be sure to write
and not
Folle64 made a mistake and put a coma.

Oh, yes. I'm sorry -_-