import ( "fmt" "os" "github.com/dotcloud/docker/utils" ) type MyFataler struct {} func (f *MyFataler) Fatal(err error, message string, args ...interface{}) { fmt.Fprintf(os.Stderr, message+"\n", args...) os.Exit(1) } func main() { var f utils.Fataler = &MyFataler{} err := doSomething() if err != nil { f.Fatal(err, "Failed to do something") } //... }In this example, we define a custom implementation of the "Fataler" interface called "MyFataler". This implementation simply prints the error message to stderr and exits the program with a code of 1. We then use this implementation to handle fatal errors in our application by creating an instance of "MyFataler" and passing it to functions that require a "Fataler". Overall, this package provides utilities for handling errors in Docker and defines common interfaces like "Fataler" that help ensure consistency across the codebase.