I wonder if a more PHP-ish and less C-ish syntax would be more readable:
```php
    $queryClauses = implode( 'AND', [ 
        Utilities::valueForField( 'wid', $this->config->getCityId() ),  
        Utilities::valueForField( 'is_video', 'true' ),  
        Utilities::valueForField( 'ns', \NS_FILE )  
    ] );  
    return "({$queryClauses})"; 
```