internal override TypeUsage GetTypeUsage()
        {
            if (_typeUsage != null)
            {
                return _typeUsage;
            }
            Debug.Assert(_typeSubElement != null, "For attributes typeusage should have been resolved");

            if (_typeSubElement != null)
            {
                var collectionType = new CollectionType(_typeSubElement.GetTypeUsage());

                collectionType.AddMetadataProperties(OtherContent);
                _typeUsage = TypeUsage.Create(collectionType);
            }
            return _typeUsage;
        }