private void collect(Set<CtMethod> result, CtClass c) {
        if (c == null) {
            return
        }

        result.addAll(c.declaredMethods.findAll { isPublicApi(it) })

        collect(result, c.superclass)
    }

    private boolean isPublicApi(CtMethod method) {
        return Modifier.isPublic(method.modifiers) || Modifier.isProtected(method.modifiers)
    }