In our Ftrack installation, we have defined a custom attribute at the project level--let's call it "locations". I would like to create a function that allows users to add an additional location to a project after querying that the provided argument is indeed an available option in the collection of locations. I can't find an example of this kind of query; I just need to know whether this is something attached to Session or somewhere else. So let's say locations = {'Uptown': 'uptown', 'Downt