func (e Error) Error() string {
	message := fmt.Sprintf("cannot set '%s'", e.Name)
	if e.Value != nil {
		message += fmt.Sprintf(" to '%v'", e.Value)
	}
	return message + fmt.Sprintf(": %s", e.Reason)
}
Error implements the error interface.
package config
import (
	"fmt"
	"sort"
)
type Error struct {
	Name   string       
	Value  interface{}  
	Reason string       
}