Method reflected = method.getNativeCall().getMethod();
JRubyMethod annotation = reflected.getAnnotation(JRubyMethod.class);
int required = annotation.required();
int optional = annotation.optional();
boolean rest = annotation.rest();
if (required > 0 || !rest) {
MethodHandle arityCheck = Binder
.from(site.type().changeReturnType(void.class))
.insert(0, new Class[]{int.class, int.class, boolean.class}, required, optional, rest)