运行Kohana数据库迁移时出错

Question

我正在使用Kohana php框架，当我尝试运行minion时，我遇到了这个异常错误：

PHP Fatal error:  Call to undefined function __() in /system/classes/Kohana/Kohana/Exception.php on line 53
PHP Fatal error:  Call to undefined function __() in /system/views/kohana/error.php on line 64

这是Exception.php中的代码：

public function __construct($message = "", array $variables = NULL, $code = 0, Exception $previous = NULL)
    {
        // Set the message
        $message = __($message, $variables);

        // Pass the message and integer code to the parent
        parent::__construct($message, (int) $code, $previous);

        // Save the unmodified code
        // @link http://bugs.php.net/39615
        $this->code = $code;
    }

这是error.php中的代码

{<?php echo __('PHP internal call') ?>}