Gmod playermodel hand help

Hello everyone. I just have a quick question about how to add custom hands to playermodels. You see when I add playermodels to my server I sometimes see in the code a hand model. Like this
[LUA] player_manager.AddValidHands( “SHARKS DON’T HAVE HANDS”, “models/weapons/c_arms_chell.mdl”, 0, “0” )
[/LUA]

As you can see there is this code but I just don’t know where to put it in the playermodel lua file that I use to add playermodels to pointshop. Anyways that’s my situation, thanks.