protected function getValueFromModel($model)
    {
        if ( ! ($model instanceof Model)) {
            return null;
        }

        return get_class($model)
             . static::CLASS_AND_KEY_SEPARATOR
             . $model->getKey();
    }
protected function getValueFromModel($model)
    {
        if ( ! ($model instanceof Model)) {
            return null;
        }

        return get_class($model)
             . static::CLASS_AND_KEY_SEPARATOR
             . $model->getKey();
    }
protected function getValueFromModel ( $ model ) { if ( ! ( $ model instanceof Model ) ) { return null ; } return get_class ( $ model ) . static :: CLASS_AND_KEY_SEPARATOR . $ model -> getKey ( ) ; }
Returns the value for a single related model.

@param Model|null $model
@return mixed|null
Returns the value for a single related model .