public function isAttributeChanged($name, $identical = true)
    {
        if (isset($this->_attributes[$name], $this->_oldAttributes[$name])) {
            if ($identical) {
                return $this->_attributes[$name] !== $this->_oldAttributes[$name];
            }

            return $this->_attributes[$name] != $this->_oldAttributes[$name];
        }

        return isset($this->_attributes[$name]) || isset($this->_oldAttributes[$name]);
    }