file.Exists help

what is the second argument for file.Exists supposed to be? Maurits.tv says it is suppoled to be a boolean, but the error says it is supposed to be a string.

“DATA”, “GAME”, or “LUA”

These are the GMOD 13 changes: https://docs.google.com/document/d/1khSuIYrAMkqXu7wlH5YRJNwz6hOH6Xqi5lqBhE3x6gA/edit?pli=1

thank you