well it depends what you want achive...if `""` is also valid value and you want switch only "yes" to "no" then it should be this one
```
dcb_default = "no" if card["driver"] == "bnx2x" && dcb_capable == "yes"
```

so it depends what is your goal. swithc only if yes is set, or always have for Broadcom cards value "no" ?