I'm writing a simple library to assist with common assertions. 

```
type Test interface {
    Fatalf(string, ...interface{})
}

func IsTrue(statement bool, message string, test Test) {
    if !statement {
       test.Fatalf(message)
    }
}

```

I noticed that the `log` package actually has a compatible implementation of `Fatalf(string, ...interface{})` and it'd be great if the `IsTrue` method could be invoked accordingly:

```
IsTrue(false, "false wasn't true", log)

```

But I get the error `use of package log not in selector`. Is there any way to use or wrap a package to make this pattern work or is this not possible?