If the contents of a collection are never used, then it is useless and therefore unnecessary. This adds performance overhead, obscures the code, and may indicate an error in the logic.

Either remove the collection if it is no longer needed, or ensure that it is used as intended.

In this example, the property Names returns the wrong collection (genres). This logic error means that the names collection is populated but never accessed.

The code is fixed by returning the correct field for Names.