@Override
	public boolean retainAll(Collection<?> c) {
		return store.keys.retain(c, KeySpan.ALL);
	}
This provides the implementation of {@link Map#keySet()} for {@link DBCachedObjectStore#asMap()}
Ghidra/Debug/ProposedUtils/src/main/java/ghidra/util/database/DBCachedObjectStoreKeySet.java