bad name. It is not intuitive. I think that something like `expect_scr_call_for_ip_forwarding` and BTW I don't like how you depend on instance variables, so something like
```
expect_scr_write_ip4_forwarding("1")
expect_scr_write_ip6_forwarding("1")
```
to be much more readable and less magic and more explicit what you actually do.