Opal Labels API

## Labels OverviewIn Opal, Labels are a useful way of categorizing resources to be filtered or grouped.### Label InheritanceLabels follow StoryFirst inheritance rules. This means that **Content** inherits labels from **Moment** which inherits labels from **Story**. **Content** also inherits labels from the selected **Account**. If a **Moment** belongs to more than one **Story**, labels are inherited from all related stories (i.e. the labels inherited comprise the union of the labels for each story).For example:Inheritance is "broken" when one or more labels is explicitly set directly on a resource. For example, if you set the labels _x_ and _y_ for a piece of **Content**, that content will then only be considered to have exactly the labels _x_ and _y_ and no longer the labels of its parent **Moment** or **Story** (or associated **Account**). The default behavior of the Opal Web frontend is actually such that when **Content** gets explicit direct labels, it takes on all existing inherited labels _and_ the new direct labels, but it does not gain new inherited labels going forward. This behavior is achieved by requesting all of the current labels for that **Content** and then explicitly setting the new labels to all existing inherited labels plus the new labels.Inheritance can also be broken by explicitly setting labels on a **Moment**. Using our _x_ and _y_ labels again:Notice that **Content** still inherits from **Moment** and **Account** even when **Moment** stops inheriting from **Story**.