@BIF
public static EAtom is_builtin(EObject m, EObject f, EObject a) {
EAtom mod = m.testAtom();
EAtom fun = f.testAtom();
ESmall ary = a.testSmall();
if (mod == null || fun == null || ary == null)
throw ERT.badarg(m, f, a);
BuiltInFunction bif = BIFUtil.getMethod(mod, fun, ary.value, false, false);