Race Editing

[Enforcer84]

So I'm making some subraces and one of them gains the mobile feat at 3rd level.

So I've tried using this:

~ If we're disabled, do nothing
doneif (tagis[Helper.Disable] = 1)

if (#totallevelcount[] >= 3) then
perform hero.assign[ft5CMobile]
endif

but my perform hero.assign line is incorrect, any ideas what I'm doing wrong?