package check import (	"fmt"	"os") // ReadableError is just a structure contains readable message that can be// returned directly to end user.type ReadableError struct {	Message string} // Error returns the description of ReadableError.func (e ReadableError) Error() string {	return e.Message} // NewReadableError creates a ReadableError{} from given message.func NewReadableError(message string) ReadableError {	return ReadableError{Message: message}} // ErrorForExit check the error.// If error is not nil, print the error message and exit the application.// If error is nil, do nothing.func ErrorForExit(name string, err error, code ...int) {	if err != nil {		exitCode := 1		if len(code) > 0 {			exitCode = code[0]		}		fmt.Fprintf(os.Stderr, "%s: %s (%d)\n", name, err.Error(), exitCode)		fmt.Fprintf(os.Stderr, "See \"%s --help\".\n", name)		os.Exit(exitCode)	}}