gump.class.php
public static function set_error_message($rule, $message)
    {
        $gump = self::get_instance();
        self::$validation_methods_errors[$rule] = $message;
    }
public static function set_error_message($rule, $message)
    {
        $gump = self::get_instance();
        self::$validation_methods_errors[$rule] = $message;
    }
public static function set_error_message ( $ rule , $ message ) { $ gump = self :: get_instance ( ) ; self :: $ validation_methods_errors [ $ rule ] = $ message ; }
Set a custom error message for a validation rule.

@param string $rule
@param string $message
Set a custom error message for a validation rule .