public function set($key, $value=null)
    {
        // Set the time that this token was saved for the first time
        $this->setAcquisitionTime();

        if (is_null($value) && is_array($key)) {
            // An array of attributes was passed in so save each one
            foreach($key as $attribute => $value){
                $this->setValue($attribute, $value);
            }
        } else {
            // Not an array so just set the attribute
            $this->setValue($key, $value);
        }
    }