import "github.com/cloudfoundry/cli/cf/requirements" func main() { req := requirements.NewDomainRequirement("example.com") err := req.Execute() if err != nil { fmt.Println(err) return } // continue with domain specific functionality }In this example, we create a new instance of the DomainRequirement with the domain name "example.com". We then call the Execute function to ensure that the domain exists and is available for use. If an error occurs, we print it to the console and exit the program. If no errors occur, we can proceed with any domain-specific functionality.