/** Remove stuff from an unordered collection. */
 private void simpleRemoveFromCollectionChangeRecordWithoutOrder(
     Object referenceKey,
     Object changeSetToRemove,
     ObjectChangeSet changeSet,
     AbstractSession session) {
   EISCollectionChangeRecord changeRecord =
       (EISCollectionChangeRecord) changeSet.getChangesForAttributeNamed(this.getAttributeName());
   if (changeRecord == null) {
     changeRecord =
         new EISCollectionChangeRecord(
             changeSet, this.getAttributeName(), this.getDatabaseMapping());
     changeSet.addChange(changeRecord);
   }
   changeRecord.simpleRemoveChangeSet(changeSetToRemove);
 }