If I set these options to extracts data from an image: ```javascript options = { xmp: { pick: ['AltTextAccessibility', 'ExtDescrAccessibility'] } }; ``` I get all XMP fields in the output, not just `AltTextAccessibility` and `ExtDescrAccessibility`. Is that “normal”, or a bug? If it's normal, I guess I didn't understand [the docs about `pick`](https://github.com/MikeKovarik/exifr#optionspick).