src/Validation/ErrorHandler.php
public static function set($error, $key = null)
    {
        if ($key) {
            static::$error[$key][] = $error;
        } else {
            static::$error[] = $error;
        }
    }
public static function set($error, $key = null)
    {
        if ($key) {
            static::$error[$key][] = $error;
        } else {
            static::$error[] = $error;
        }
    }
public static function set ( $ error , $ key = null ) { if ( $ key ) { static :: $ error [ $ key ] [ ] = $ error ; } else { static :: $ error [ ] = $ error ; } }
Set specific error.

@param $error
@param null $key
Set specific error .