import (
    "errors"
    "fmt"
)

func ThrowError(throwError bool) error {
    if throwError {
        return errors.New("This is an error")
    }

    fmt.Println("No error was thrown!")
    return nil
}

func main() {
    ThrowError(true)
    ThrowError(false)
}

const (
    ErrNotFound   = DictionaryErr("could not find the word you were looking for")
    ErrWordExists = DictionaryErr("cannot add word because it already exists")
)

type DictionaryErr string

func (e DictionaryErr) Error() string {
    return string(e)
}